I just wanted to let folks know that I'm aware of some efficiency concerns on Svidgen. Namely, your Heros' Bookmarks list and tag autocompletion for <user x's=""> Bookmarks have the potential to operate very inefficiently. The latter issue deals with the order in which tags are being filtered. And there's actually a two-stage optimization that I'm considering there. I have some ideas for the former issue, but it's less likely to be an issue until the site grows in popularity. You probably haven't even noticed that one.
So, in short, if you're experiencing some particularly high tag autocompletion latency, know that I'm aware of it. And I'll try to have an optimization in place within a week or so.