You're right, it takes longer to upload a page than to download it. And image gallery-like pages take long (I know because I save Imgur pages now than then :)). But in practice, this isn't a problem.
There are a couple of heuristics to avoid wastefully uploading pages: the full page is uploaded only if the reader expresses "sufficient interest" in the page. Currently the heuristic is 90 seconds of continuous reading of a page, or scrolling to the bottom. If a page is read for a minimum of 10 continuous seconds then only the text of the page is uploaded.
Static assets like JS files benefit from deduping: they take time to upload the first time, but subsequently processing them is much faster.
Typically, people read multiple pages in a browsing session: I rapidly open many tabs and then read each one for multiple seconds. There's a debug mode in Purple Rails in which a timer counts up when I switch to a tab. I find that typically spend 100+ (usually much more) seconds on a page that I read through to the end. This is usually enough time on a residential broadband connection (I have Sonic DSL) to finish uploading a page. I also use Purple Rails on a tethered 4G connection almost everyday: uploading is slower than DSL but it works.
Basically, by the time you finish reading a tab, the previous tab you read would have finished saving.
There are a couple of heuristics to avoid wastefully uploading pages: the full page is uploaded only if the reader expresses "sufficient interest" in the page. Currently the heuristic is 90 seconds of continuous reading of a page, or scrolling to the bottom. If a page is read for a minimum of 10 continuous seconds then only the text of the page is uploaded.
Static assets like JS files benefit from deduping: they take time to upload the first time, but subsequently processing them is much faster.
Typically, people read multiple pages in a browsing session: I rapidly open many tabs and then read each one for multiple seconds. There's a debug mode in Purple Rails in which a timer counts up when I switch to a tab. I find that typically spend 100+ (usually much more) seconds on a page that I read through to the end. This is usually enough time on a residential broadband connection (I have Sonic DSL) to finish uploading a page. I also use Purple Rails on a tethered 4G connection almost everyday: uploading is slower than DSL but it works.
Basically, by the time you finish reading a tab, the previous tab you read would have finished saving.
Like I said, nothing too fancy.