A bit too social?

I've been looking at adding some more features to the greatest PHP CMS around and decided that simple social bookmarking doohickeys would be useful. The idea is to have a little panel in the admin area where you can check which ones you want listed on your page. Straightforward enough so far, right? Nothing groundbreaking or difficult or anything.

It got tricky when I started trying to figure out what sites should be included. It turns out that while I wasn't looking, social bookmarking sites became quite popular. Full points go anyone who can name them all.