My problem with bookmarking tools is that I horde links in them that I actually never go back and look for. I usually just use my brain as an index for some keywords and then utilize Google search.
I should add that I've pretty much given up on bookmarking tools because I've left a trail on delicious, the old Google one, Springpad, Clipboard, etc... I'm not just using plain-jane Notational velocity notes, and I'm pretty diligent in writing why I'm saving a link, whether it's an interesting library I need to use some day, or a good article that I read where I learned something. I'll usually summarize what I learned.