Joking aside, that's actually a good idea. There was a project or addon for Firefox that attempted to do something of the sort I think. Though, I can't think of the name so it probably isn't particularly common.
I've actually taken to breaking up my browsing sessions across multiple browsers as well: One Firefox profile for generic browsing, links, Youtube, etc.; one profile for development documentation (further broken down to individual sessions organized by project or language using
Session Manager); and one profile for development/debugging. Chromium is relegated to static tabs like the goon site and Hacker News. I then filter out the clutter of tabs in Chromium to bookmarks, but oftentimes that doesn't work.
Bookmarklets are handy, but I'm not sure "tagging" bookmarks is a viable solution in the long term. I've created so many tags in the hopes I might remember what went where that I've effectively given up all hope of finding anything I need. So, I just do a search for it.