I used to do that in other fandoms, but I'd never get back to reading anything. I've got over 3000 fics bookmarked in a 'to read' folder, in five different fandoms. I never remember to delete the bookmark if I do read it, because I usually end up reading things I've bookmarked when I see someone posting about them.

Except for the window not warning me and getting dismissed, the leaving tabs open has been more effective in actually getting around to reading things, and then I just bookmark the stuff I want to remember later.

I really should make use of AO3's features more, but I've got more than one ID there so I'm rarely logged in.