I manage a few decently sized blogs for authors and bloggers. From all the checking I've done for these buttons, only Email To A Friend, Facebook, Twitter, and

I manage a few decently sized blogs for authors and bloggers. From all the checking I've done for these buttons, only Email To A Friend, Facebook, Twitter, and G+ are worth doing. The others might get 1-10 clicks vs the aforementioned few getting thousands of clicks (or hundreds for G+). I've gone to just putting Facebook/Twitter/G+/Email, as minimally as possible.