I've just updated to Firefox 55 to test this, and the improvement is ridiculous. I hope that Firefox focuses more on power users in the future.
I'm curious what the author uses to manage all of these tabs. I use Tab Groups, but I think they won't work in a few Firefox versions so I'm looking for alternatives.
This is fucking surreal. Why on Earth would anyone want 100 open tabs, besides testing? What's the real life scenario we're looking at here?
For example, say I'm booking a trip. I always open a bunch of sites (Kayak, Booking.com, lots of hotels, Google Maps, places to visit, etc.) in a single window. In pre-computer times it would be like covering a desk with a ton of papers, books and notes. Gradually I will figure out stuff, book the trip, etc. but the tabs can stay for quite a while.
I feel like many "dozens of tabs" windows are little projects like this. For example, doing development I typically have a bunch of documentation tabs open. We keep these windows open because there's no way to stash them into a drawer while they're not actively being worked on.
What browsers lack is a good way to treat these tabs as "persistent workspaces". I'd like to be able to close a window and be able to return to it later. Rather like an IDE which remembers your open files. So I wish I could "save" a window (as a "workspace") under a name, after which every action would automatically update the saved workspace. Close the window, workspace stays saved. Open the workspace, everything is restored.
There are some browser extensions that allow saving groups of tabs, but there aren't any that behave like I described above.
It lets you save and group open tas and windows, plus export them as list. (No affiliation)
I think there is a new Firefox experiment that behaves somewhat like this: https://testpilot.firefox.com/experiments/containers
Container tabs is totally different, that's about basically having multiple profiles in one window. E.g you can have the work container logged into your work email and work stuff, and your personal container logged in to your personal email and personal stuff, and they don't know about each other. Like incognito, but persistent and within the same window.
The 'simplified' in its name makes me doubtful it has any of the advanced features I need.
These "redone" addons that work post 57 start out pretty bare-minimum but they rapidly gain features.
Tab Groups has a shot. I took on this project after it was
decided to remove the built-in Tab Groups from Firefox, as
I thought it could be a good and fun learning experience;
it hasn't been, if anything it's been stressful and
time-consuming. I don't really use groups outside of my
development profile, with my browsing habits I only find
them useful to a point, they're helpful for my
development/coding workflow, but I've used them maybe twice
in my main profile during normal browsing.
Its core functionality and basic workflow probably can be
made into a WebExtension, but only after an almost complete
rewrite of the code (with some major work done on Firefox's
side as well!), and still stripped down of at least some of
its features. Many of the new groups features I've wanted
to add since the beginning are impossible though, for the
same reason as I mentioned above: they either don't fit the
scope of what can be allowed through WebExtensions or their
implementation would be far too complex to do on my own.
I have 7 groups right now on my home machine, and that many or more on my work machine. Each has a few to a large number of tabs in it. I have about 28 in my current one. Each group contains tabs about a different topic, such as daily visit sites, searches and articles for ongoing development in a particular language, research into specific projects, or random lookups.
I also use the Tree View Tabs extension which show tabs in a hierarchical list on the left, instead of across the top. This is a better use of space for me and shows the relationships of tabs.
I am going to miss both of these severely if the XUL plugins go away this fall as they are saying. My web workflow is much more efficient with them, at least in Firefox. I like using Chrome, but with a lot of pages open I just have a squished up mass of tabs across the top that can't be easily read, it's a big bother.
Anyway, I wish there were more extensions for more browsers that improved the state of managing large groups of tabs by topic.
Workaround is to always quit firefox using the ctrl+q shortcut, though at times groups will reopen with the correct number of tabs but they're all empty.
Best bet is to manually save your session at times.
It's impossible to go back once you get used to that UX.
There's also tab groups and tab groups helper but those are about to disappear and make firefox useless for this use case.
My project context has a chrome window with all my task related tabs, my terminal window and my IDE. My communication context has my tickets, slack and other communications in it. Then there is one more context with podcasts, spotify or non project docs and reading.
It wasn't something I set out to achieve either, it just happened naturally once I started using shortcut keys to switch between workspaces.
Naming would be too much explicit action for my taste (might as well go back to the lost ancient art of bookmark management), but I think most usage patterns of grouping tabs in windows would work much better if each window had some kind of designated primary tab (leftmost tab?) defining a more permanent window identity than using whatever tab is currently active for window naming.
Planning a trip is spot on for my gripes with ephemeral browser window names: "The Maps Window" might have a hotel website currently active (that might get promoted to its own window if the hotel makes it to my shortlist) while two of five windows for candidate hotels have a maps tab (individual hotel surroundings) active. Now every attempt of going back to "The Maps Window" will be a voyage big enough to forget why you wanted to look at maps in the first place.
If bookmarks are deprecated I'll have to save workspaces made up of a single page and I'll just feel silly.
Edit: Plus you can use bookmark folders as workspaces already I guess? I don't but you can, fairly easily!
Let a group of tabs be a bookmark folder that has the "show" attribute set, and so dynamically tracks what is shown.
Want to show all tabs in a group/folder? Toggle show.
I use wallabag instead which is basically bookmarks with a local snapshot of content that you can easily classify and sort.
Not related anyway except as happy user
FF allows you to bookmark all the tabs you have open into a bookmarks folder.
It also provides a button at the bottom of the folder "open all in tabs"
This works well enough for my taste, but I also use pinned tabs for stuff like fb messenger
Not even mentioning dealing with managing several thousands of bookmarks, duplicates, link rot, and so on. Definitely impractical for power users use case.
Why abuse the browser in this way? Tabs are a fifo buffer for web pages. Opening something in a new tab allows one to read/act on it when the current tab is closed, without interrupting the mental state / flow relating to the current tab. Pages loaded in new tabs are also opened in the background, so there is no interruption while waiting for pages to load.
From 2009, so rather ahead of the curve.
Looking at my current open tabs, most of them are dense "boring" reading material like scientific papers (or reddit/HN discussions of them.) I feel they are important to read but don't feel motivated to do so ever.
I've never gotten to 100 tabs before. For entirely practical reasons, that Chrome can't handle it. It runs out of memory and grinds my computer to a halt. So I had to triage away the least important tabs and bookmark them or force myself to read them, just to keep my computer running. I just starting using firefox though, which is not helping this bad habit.
I don't believe it should be up to the browser to deal with tabs.
I don't actually believe tabs are a particularly good representation of browsing.
Using extremely light browsers such as surf (http://surf.suckless.org)
in a good window manager such as i3 (https://i3wm.org)
makes each page a first class window, without any browser clutter.
You soon learn to browse with as few pages open as possible.
Opening new tabs is a promise to spend time in the future.
Using simpler linear navigation helps keeping focus.
I want to know why I'm browsing, not hoping that I go through every tab
that I lazily felt I might need to see in some open-ended future.
The web is broken but with some effort
you can alienate most of the cruft from your usage.
I've tried all the third-party type attempt to solve it (everything from saving the links in a textfile I always keep open to ReadItLater, OneTab, Pocket etc. All those things are where tabs go to die, never to be read again. More like ReadItNever, amirite?). That's a "solution" I guess.
Now I try to be more selective in what I "keep" to read later, and as soon as I hit 40-50 tabs, I go through and kill a bunch of them. It hurts a bit, but not as bad as when I have hundreds of tabs.
You are not alone.
I've never gotten to 100 tabs before. For entirely practical reasons, that Chrome can't handle it. It runs out of memory and grinds my computer to a halt.
Yep, been there before too. My "light" laptop only has 6GB of RAM, so Chrome starts to dog out pretty quick if I go tab crazy on it. It can handle about 25 tabs and then it starts freezing the entire system for minutes at a time.
Fortunately my "big" machine has 32GB of RAM and an i7 processor so it can handle 4 or 5 Chrome windows each with oodles of tabs, 2 or 3 Eclipse instances, and various server processes all running at the same time. I just can't bear carrying that thing around because it weighs a frickin' ton. :-(
I also have to run a FF and a Chromium (two separate Google accounts is basically unmanageable without separate browsers). This is enough to fill 8GB. Good Lord the web is fat these days.
I also use chrome profiles to separate my workspaces, so I don't have to load everything all the time and search through my tabs to find the one I want. I even sync them to different accounts.
You can use Firefox's container tabs for this.
Like you said about the boring material. I wouldn't think of them as boring. But detailed, and basically takes a long time to grasp. I will need to spend at least an hour or two on the topic. And i since it is not the most important things in life This two hours schedules gets put away for the time being.
Then there is the Apple News tabs hoard which happens in Apple Events.
If I see a tab open that I haven't looked at in a while, I try to make the effort to either submit it to Pocket or Pinboard, and then close it.
You could argue that's just moving the problem elsewhere, but I like to think I'm making at least some organisation effort.
The feature I like best about diigo is for what I do read, I can highlight the sentences I want to recall or locate later.
But I have on more than one occasion been unable to remember how I got to a page, or even how to search for it, and in those times I found my system invaluable.
Less out of sight as well, the next time I do a google search, diigo plugin injects my existing stuff beside the search. I like the offline copy it keeps for me like you said.
It's not perfect but not a sinkhole of bookmarks.
Chrome also just tinifies tabs as you add them (eventually making them little slivers that are hard to click on/close and impossible to identify), whereas Firefox stops shrinking them at one size and then lets you scroll through them. This itself makes it easier to have more tabs. So if you're a Chrome user having 100 tabs may feel excessive, but given that the experience is pretty pleasant in Firefox a lot of folks have workflows around this. If something is hard to do you'll never discover workflows that need that functionality :)
On top of that, the addons I mentioned make the experience even better.
For me I have >100 tabs often because I'm working on many things, and each thing may have 3-5 tabs open (github issues, code, a million documentation tabs), and I'm also reading news articles and such, and often queue up things to read later as more tabs that I get to eventually. Pretty easy to get there.
And I'm very happy about better support for this kludge, but I do wish that someone would get to the roots of the needs that cause this use of tabs, and design the correct interface for it instead.
You could create visual groups and lay out sets of tabs and even name the sets, and switch between them at will. It was awesome.
From the way you describe it I think it sounds like a great start for at least some of the needs driving this. I suspect in many cases heavy multi-tab use comes from a need to lay out sets of documents for use together in some sort of spatial metaphor.
The traditional desktop model often does a pretty good job of covering this for local files and native programs, but I find browsers to be far weaker at supporting it.
As a complement, for the potentially-life-changing(-but-not-right-now-for-goodness-sake) things and other valuable resources I will almost certainly never find my way back to otherwise, I think it might be a nice start if I had a 1-keypress way to drop them, with metadata, into an local, indexed archive. The followup challenge to that would be a really good interface to getting stuff out again.
Tools like Zotero could in principle cover the first part of this niche automatically already, but I wouldn't want the backlog archive (sluggishly) dropped together with my references without any shadow of compartmentalization, so I don't really view that as a ready solution.
It also has a very interesting fresh take on history.
I also research a project and then wait a while before starting it. This helps me get a better perspective on the project. I'll often leave my research open in a tab group so that when I start the project I can very quickly review everything and get up to speed. Using bookmarks in this scenario doesn't really work because bookmarks don't save session state very well.
The point made is that different people will use software in different and unexpected ways. Assuming that people use browsers the same way you do, or assuming that a certain scenarios are "impossible" because you personally are not likely to encounter it will harm your userbase.
Also many of us (I think) use some kind of vertical nested tabs.
Just an example: I'm working on an ML model, I begin by researching prior work. I get down to 100 or 200 related papers in google scholar. I start going through the papers until I find the ones that are closest to what I'm looking for. I leave the tabs of the 10 or so papers that I have found open. Now I have 12 tabs open: 10 related papers, my specific google scholar search and my general google scholar search. As I go through the related papers I will happen upon different ideas, libraries/tools or referenced papers that I want to return to. These tend to build up and you can easily get to 6 or 7 per paper. By the time I finish 4 related papers I could have 40 tabs open. This whole process happened over the course of 30-40 minutes. I also tend to find new keywords to use in google while I'm reading these papers which I then produce more google scholar searches from and repeat this same process over again. Now imagine having done this many times over with various projects you're working on but not necessarily required to finish. That's how you end up with a few thousand tabs in onetab and 400 tabs open in chrome.
If I google something, I like having a few different sources or points of view, so I open a bunch of tabs to look through.
Sometimes, I want to switch to a different task, so I collapse that tab tree for looking at later.
Sometimes, inside that tree, there's another topic of interest I want to know about, so I create another tree (with 3-5 tabs for different sources) inside.
I have a tree for music, various trees for work, various trees for interesting topics, leisure, etc.
So some of us think 100s of tabs are weird, because there's no way we could get any work done, before closing down those tabs.
Or, if you want to look at it the other way, bookmarks are just tabs that don't load until you click on them.
All the bookmarks I have ever saved in my life on any browser remain without being touched because it's just another bunch of stuff hidden away with no context or relationships. So I stopped using bookmarks a long time ago (for frequently accessed sites, the Awesome Bar fulfills the needs). I have the same attitude with all the bookmarking and "read later" services. For me, if something is out of sight, it soon gets out of mind. This is where tabs help me focus on different subjects/areas much better than bookmarks (or even a page that has all tabs listed). I can easily find what I had put in a group of tabs and decide when to get to them. It's not perfect. Sometimes I find that some tabs are no longer interesting or that I don't have time for them, and so close them after several days or weeks.
I've seen some experimental stuff from Mozilla on improving bookmarking and addressing the issues with "save for later". One such effort was Dropzilla  in 2012, which I was impressed with. But it seemed like that was abandoned soon or not carried forward (if anyone has updates on this that I may have missed, please let me know).
Firefox has also been, in my experience (not meaning to start a browser war here), much better at memory management. In comparison, I consider Chrome as a toy that's useful as long as you don't want too many tabs (otherwise it just brings the system to a crawl). Stability wise too, I find Firefox extensions to be of much better quality. To date, I can't get session restore working well or undoing tab close working well in Chrome. Same goes for switching proxies quickly and other things too.
So, what I need is a browser that can handle hundreds of tabs well. For me that has always been Firefox, ahead by far.
- client asks for a say an audio player integration into an app
1. Research bunch of open-source audio player libraries available on Github. This is easily 20+tabs
2. Additional, sometimes temporary tabs get opened when researching individual libraries (like their documentation page, etc)
3. I want to pick a library, save the state if this research and go to implementation. (I create a new window)
4. Open documentation for the library or its Readme and start implementing, use Google, or stackoverflow.com as needed. Save state of this (don't) meaning, don't close it;nowadays i use bookmarks if it's a task i wont get back to soon)
Now, I'd have a bunch if tasks like this. Personal, professional, hobby projects, etc. Tabs should be cheap and should be lazy loaded. You should even be able to hibernate tabs manually (Vivaldi (chrome clone) let's you do this)
Whenever I find something interesting, i open it in a new tab, read it little bit and leave it there thinking - I will get back to it later which never happens. Later on when it is getting enough that I can't open a new tab then using tab-snap extension I copy list of all the tabs open and email it to myself. This email list is like my own mini knowledge dump which have helped me retrieving things later on when required.
The reason being that session management is terrible or non existent and bookmarks is horribly broken.
With firefox I have a bunch of extension and groups my tabs by activities. I guess some power users do so because it's more convenient and practical than having to remember one or two dozen URLs and reopen them when coming back to an activity later on.
edit: This was one of the reasons I loved the old Opera. It just didn't care. 50 tabs, 100 tabs, 200 tabs .. it just worked. I miss it.
It's easy to cross that threshold when you're doing research.
30 more for each comment page
20 for google news
10 for wikipedia (conservative)
at least 20 per tool's documentation section, since all docs are now broken down into a hundred 5-kilobyte files, it seems
20 to research cheap action cams on Amazon
10 to go through some configuration guides for a cloud product
10 for random facebook feed links
and 10 for youtube rabbit-holing
So, 160 tabs I have open. It's a slow evening.
On desktop I have 4 pinned tabs, Gmail, workflowy, trello, google Calendar. Plus anywhere between 2-30+ tabs, depending upon the google term i am searching, or reading something. And none of these is Facebook Youtube Medium and such, as all these are blocked.
The secondary work phone has 52 tabs.
Terrified of loosing all these, occassionally I use desktop google chrome option of open all tabs on other (mobile) device, and then export all those tabs to a html file.
It's not surreal if you think about it.
People put off cleaning there room and such... so there are bound to be people who put off reading tabs they see interesting.
If you're going to say book mark it then no. My bookmarks are a mess.
I've sent Mozilla a suggestion of doing machine learning and cluster my bookmarks for me. >___< Also if they can have topic labeling ml stuff on book mark that would be nice.
which is your favorite?
Fixed it for you. Like another person wrote, old Opera did it just fine in a period where PCs were much slower.
Doesn't matter. They're there for a reason. And there's still something a touch "different" about a tab, compared to a bookmark. It's hard to explain, but there really is a purpose to doing things that way.
Then I close the whole parent tab and sub-tabs when I'm done with a particular context, or go through my to-read-later tabs to catch up and close them.
However i force myself to clear everything on startup.
By the way, there are extensions that will kill tabs that are inactive, but even on my 16GB MacBook Pro it doesn't take much for Chrome to start weighing things down.
I'm on beta. Had a few hangs last week but this week it is buttery smooth as usual.
Have you ever used CloudFormation?
I can easily have over 100 tabs of just Reddit open.
okaay, so there's now 10 potential useful articles to read, they're already loaded (yippee, saves time...) hmmm let's go through them hmm... that one's useless (close) that one's useless (close) that one looks interesting but i don't have time to read it immediately....
---->>> LET'S KEEP IT OPEN FOR NOW * <<<< ----
.... and move on whoops the phone's ringing i have to deal with a client's urgent issue, he also needs something to be fixed okay so it's an obscure issue i don't know anything about let's do some google searches damn we're under time-pressure again let's do the same trick, right-mouse-button on a stackexchange liiink, right-mouse-button open-in-new-tab on a forum paaaage, right-mouse-button on some git repository browser because i might need to compile that up or investigaaaate...
okay now the tabs are open and loaded don't have to wait for them to load let's review them... close, close, read, read, close, read.... hmm that looks like it's got the info i need, but...
---->>>> LET'S KEEP THE TAB OPEN IN CASE I NEED IT AGAIN TO FIX THE CLIENT'S PROBLEM IN THE FUTURE <<<<<----
okaay so i have time to go back to that particle physics research now and i can carry on where i was interrupted ...
--->>>> * BECAUSE I LEFT THE TABS OPEN.... * <<<<-----
repeat, repeat, repeat, repeat. the technique saves vast amounts of time (through proper use of parallelism), uses the browser itself as a proper research tool, as well as an information storage mechanism "with history". the actual "browse history" itself i have found to be pretty damn useless, i can never find anything as it doesn't have a proper useable UI.
from your enquiry i should imagine that you're one of these people who sits there waiting for a page to load, sequentially, then closes it... sequentially. depth-first in other words. by which time it's been so long that you've forgotten what you were searching for. for those people who use internet search engines to do breadth-first searches, tabs are absolutely invaluable.
I have a group of tabs for various things in AWS, a group for various things in my build system, a group for the various Jira and Confluence things, a group for mail and google docs, a group for my company's HR requirements (timesheeting), a group for programming docs, and any one of these groups can have additional tabs for idle browsing while I'm waiting for something, and I can add additional groups if I'm on a secondary project.
The way I tend to browse is to hit a page, then load several promising links in new tabs. Load them over the network in parallel, because doing everything on one tab with back/forward is painful in the extreme.
Overall, it's ridiculously easy to hit 100 tabs.
Edit: fantastic, thanks for the suggestions. Will definitely check them out.
not as nice as the old one (but it's improving!), I just use Tab Center Redux.
But it should be a core feature of the browser itself IMHO.
I guess I should use it in tandem with that plugin that replaces 404 pages with archive.org links...
I'm sympathetic, I use my two secondary 1080ps in portrait. I think I used to use a vim plugin on Chrome that had a sublime-ctrl+p-like feature to just search through my open tabs for the one I wanted.
I've tried to coach her on working with the bookmarks better, but she has her system, and she's sticking to it. And to be fair, I don't know how I would manage bookmarks in any web browser trying to deal with them at her level. She has > 30k things bookmarked that are "important" to her.
You know that feeling you get when you're watching a user do something and he or she right clicks and selects copy and then goes through the dock to find the next application and then right clicks to paste, but the target area isn't focused, so it doesn't work. So then it's back to the dock to find the prior app and then reselect the text and right-click, copy, etc. etc. etc.? You know that feeling. It hits you in the pit of your stomach like the first time you saw the alien burst out of John Hurt's chest in Alien, or the red wedding from Game of Thrones, or every time you're in a meeting with a product manager.
First, there's the shock of it. The horror. Oh. My. God. WTF is happening here? Then there's the reality setting in. Holy shit. This is real. This is actually a thing that's happening, and there is literally nothing I can do about it. Then there is the sadness. I used to think of this thing in front of me as a person. Now all I see is a dead, empty, hopeless, useless, lifeless husk of a human. An end user. With a product manager alien screeching as it runs away from the lifeless corpse of the user it just murdered. Not by intent. Simply because that's what it is: a fully alien form of life that can only exist by killing humans.
Sorry about the vivid imagery, and I'm hoping this comes across as a joke about the friction between PMs and developers. I don't actually think they are that bad.
But every time I watch my mom try to scroll through 30k bookmarks to find a link, I get that feeling magnified by about 50.
Bookmarks | Show All Bookmarks then keywords in the 'Search Bookmarks' is useful.
I have actually set the bookmark.html file as my start page. I can then use 'find in page' if I can remember any keywords about the page I am looking for, or just scroll down.
Ms Martin Senior needs to have her bookmarks backed up as well or there will be gnashing of teeth at some point in the future.
I believe Chrome is not nearly as smart as it could be about deferring loading of tabs, though.
I prefer to disable media.autoplay.enabled which is enabled by default.
I used to avoid Chrome for the same reasons, but then I found an extension and, uh, extended it, to create:
It forces all tabs into inactive state on startup. Also creates a new tab page (or switches to an existing one) to avoid loading the focussed historical tab.
I'm a Firefox user though so that's where my chrome knowledge starts and ends.
"Firefox doesn't do this" is not a valid one-sentence summary of what I just said.
I got 8 extensions installed at the moment, 6 of those are marked as legacy and will stop working before the end of the year. I also hope Mozilla focuses more on power users, but I think a lot of them will leave when their favorite extensions stops working and Google keeps favoring Chrome on their sites.
And no, Firefox WebExtensions are not compatible with Google Chrome WebExtensions. They're close, but not compatible.
I have the problem of moving a tab to a new window, and then 15 minutes later I have 15 tabs open. So I often have a few Chrome windows open at any point.
If I restart Chrome, only the focused tabs on each window are loaded.
(Related: I'd also really like to middle-click video annotations to open them in a tab. No, I don't want to replace the current video with them.)
But recent performance improvements, especially the handling of many, many tabs has me looking at FF again.
The question was about videos in a background tab, which is controlled by the media.block-autoplay-until-in-foreground setting.
EDIT: I would agree with you in your assessment of the default behavior however, if it were the case, that most people only have a few tabs open normally.
I think the main lesson is that bookmarks don't work too well or people just don't use them. If nothing else, make the bookmark display show newer bookmarks rather than the same old ones from four years ago. And maybe start preloading if they are opened regularly. Merge two features together, maybe add optional other organizational features for example similar to new tab screen.
The tricky thing is that there are a lot of things that are potentially supposed to happen while a tab is open. The browser is now it's own OS, and it may be very difficult for developers to use important features if tabs (processes) only _look_ like they are running.
IMO just one good new tab UI over a user's history/local cache could make a sizeable dent in Google's ad revenue
Try it, then read the original post and the comments again. :)
I think this is the missing piece on all this discussion.
IIRC pocket has had some serious vulnerabilites exposed.
If i don't look at a tab for a few hours, it's not worth keeping around as it just adds to the noise without providing value. If i need to read something, i either read it immediately or bookmark it to read later. The result: i can confidently resume work without distractions at any time.
> You can't just glance at the top of the
> browser to remember where you just were.
With tree-style tabs, each root represents a train of thought. I just collapse them until I decide what to do with them. Sometimes I bookmark and banish them. Sometimes I come back to that thought next weekend.
Chrome's default tabs at the top, to me, are the distraction where each tab has equal weight. But I'm not going to say that anyone is doing it wrong if that's what they prefer.
In this particular example microsoft uses edge to push people to use the latest version of their adware/spyware OS.
Neither the back button nor bookmarks retain state sufficiently or have sufficient responsiveness to replace open tabs.
I have 2-3 tabs open most of the time. If I am looking something up, I go to 10-12. When I am done, it goes back down to 2-3. I can't even fathom under what situation people are using hundreds of tabs.
I have heaps of tabs open, but there are orders of magnitude more pages in my browser history. The latter usually contains so much that is too much to look through to find anything but quite recent entries. The tabs still open are pages still with some relevance to me, while the history is filled with lots of incidental stuff that is no longer of use.
[Edit: also, with open tabs the page content is already there so it's more quickly accessible. This can be useful if you need to look at it to help find the page you're looking for, and to get the content from the page]
For me, it reduces cognitive load. I don't keep in mind all tabs that I have open -- that's why I keep them open! To forget about them.
Bookmarks are mentally for things I want to save and reuse. But I'll probably open 40 HN sourced articles (from the main page and comments) per day, and continually cycle/review them for interest/effort throughout the day.
I also close tabs as soon as I'm done with them which is why I only have 150-200 tabs open. Each categorized by activity, so when I switch one activity to the other I save time and cognitive load by having them right as I left them instead of having to find what URLs to reopen and actually open them. This way I only have 5-30 tabs open in front of me while the other are offscreen in other groups.
If browsers had a sort of tab queue where longer lived stuff then things could be a bit better on this front I think
To me, the problem is that bookmarks are "while browsing, go to a different component that loads the browser tab with what I want".
Tabs, OTOH, are a placeholder for things that I want to keep just 1 step closer.
Saying it that way, I don't think it makes rational sense. But 1 cognitive step to a page instead of two is huge for me.
A better history may solve their problem.
First you have to create some categories, but that doesn't take long and then you simply throw bookmarks in these categories. the end.