I've had a del.icio.us account for a few years now. I mainly use it to keep track of my ever expanding bookmarks. I have a few different computers and this is the easiest way I know to sync them all. i can use my own tags for different projects I'm working on (paper #3, final project) and interest. I can group them in ways that make sense only to me, but then share them with others. I've subscribed to other librarian's bookmarks, and it is a great way to discover other sites that I may have never found just through google.