AddThis Social Bookmarking
So far, I’m pretty happy with it. I haven’t seen any ads (although I do have AdBlock), and they include an analytics package that includes just enough info to be useful.
So how well has it worked? Well, people have shared my content over 420 times on Facebook, Digg, MySpace, Twitter, Delicious, StumbleUpon, and more. These may not drive a pile of traffic, but they do create a lot of good backlinks that increase my rankings in the search engines.