(Where by "entire history" I mean "all the way back to 1993" and "appropriate tags" I mean "customized for me personally".)
Because I just started using del.icio.us and it seems really nifty, but I want it to have all the stuff I've already read in the past, too, so that it'll match up with my memory, which needs all the help it can get.
And while we're at it, I wouldn't mind an extension that just read my mind so I don't have to type things. Sometimes my fingers get tired.