We added a WordPress plugin to InDesignSecrets.com that lets you Tweet/Like/Email a link to the article you're reading without having to leave the article.

I saw they were using this on Mashable.com and thought it was some fancy custom programming … and then realized I had been seeing the same thing on other blogs for months.
Out of the box, the plug-in is about 3 miles high with buttons for Digg, StumbleUpon, and more, and about 2 pixels away from the article text We customized it for only the 3 services most of our audience uses already — Facebook, e-mail, and Twitter — and all the rest are available when you click the bottom catch-all “Share” link. And we changed the offset so it floats in the blue background, which I think is much less intrusive.
Anything that makes it easier for our readers to share good links with people is great for all of us, because it brings new eyeballs and (hopefully) their intelligent comment contributions to the party. But I know change can be off-putting, and if you never use FB/Twitter, it could be aggravating. Which we don't want. 
What do you think?