A feature I wish existed in web browsers

"Temporary bookmarks"

This would be a menu where you could add temporary bookmarks to sites that would automatically expire and disappear after a set period of time.

The reason for this would be that often I (and I imagine you, too) probably want to bookmark a page or set of pages temporarily, as part of a project or something, but do not wish to add them permanently to your bookmark list or figure out where and how to organize them.

Some examples that would be useful as a temporary bookmark would be things like when you are comparison shopping for a product, you may bookmark several review or product pages, especially from different sites selling the product you are interested in; after you purchase the item, you will likely never need these again.

If you are researching a project, you might bookmark pages on your topic, which would be very useful while the project is underway, but you wouldn't need them again after the project is due.

Another common use I forsee for temporary bookmarks would be if you make a post or ask a question on an online forum, you may wish to bookmark the discussion thread to watch for followup posts over a couple-day period, but you would not want or need a long-term bookmark to that discussion.

Temporary bookmarks could be set to automatically expire after a default period (say a week or two) or the interface could ask how long you want to keep the bookmark around when you save it. This could easily be integrated into existing bookmarking systems, with a separate shortcut for making a bookmark temporary and/or a new "make temporary bookmark" command when you right-click on a link.

It seems to me this would be an innovative and highly useful enhancement to pretty much everyone's web browsing experience. What do you think?