Are you amenable to the solution "Put it in a header or give it emphasis comparable to the copyright notice rather than the title"? I think a lot of people agree with you in the abstract that it's a huge imposition to not have dates on things, but are unwilling to even right click to actually figure the date out, but they'll start doing measurable discounting of the work immediately if you do the typical thing and put the date front-and-center. I would also bet that people will simultaneously say they're not giving the date undue attention, mostly because people are terrible at introspection.
If you mean an HTTP header, no, that doesn't work, since you never know whether the thing you get there is an accident or an actually meaningful value. Putting it somewhere where it doesn't stand out is acceptable. What annoys me is if I want to know when something was written (for example because the interpretation of a reference it makes would be different before and after some historical event), and there is no way to find out.
I concur. It really irritates me that some writers feel their content must somehow be timeless and yet a year later it's superseded because something in the world changed. When I'm trying to research something completely new to me I cannot build up any kind of meaningful chronology using such posts.
I do agree that the date doesn't need to be right alongside the byline but an indication of date somewhere on the page is important.
Edit: As for people who devalue something purely because of the date, are these readers you really care about? I suspect there are annoying readers just as there are annoying customers.
That hides it from everyone but HTML pros, and even as an HTML pro myself, I'd typically not think to check the META if they've already designed the date entirely out of the visible text. (I'd instead check for 1st appearance in the Wayback Machine.)
I suspect the best hybrid strategy, for those who feel dates complete a duty to the reader, is to put the date in small, low-contrast text near the bottom. Perhaps also, when minor edits occur, update one or more similarly-subtle 'updated' dates. That emphasizes the material is not obsolete/stale, but live reference material still maintained.
I have no idea where browsers display that, and if you require obscure browser feature or source reading for people to find out the date, you are putting undue obstacles in their way.
At the very bottom, just before the backlink to the home page, I have (in a smaller font size) something like "Original publication on March 2nd, 2014, last changed on March 16th, 2014".
I don't have anything to hide, so it's there, but I don't see any real value in it for the reader. So I effectively buried it.
Do you think having both an originally published date plus an "updated on" date would fix the issue without being devious? The published date is important information to me, but if I see that the author has edited it recently it makes me feel that it has been checked to still be relevant.
I've noticed that some major sites where having up-to-date information is important, such as those providing financial or medical advice, have started adding a "last reviewed on..." indicator.
These sites also tend to have very obvious markers saying "this information is no longer maintained and only for historical reference" or "this information is no longer maintained but the new equivalent is here" where appropriate.
Personally, I find the indication that the information has been checked recently and is still current to be more important than when it happened to be published for the first time or when it was last changed.
