Twitter tools for Chrome
More About Twitter tools
After setting up your Twitter account name clicking the button opens a popup that shows links to a few Twitter tools.
You can click through to DoesFollow.com whichs shows whether a Twitter user is following your Twitter account.
You can also click through to twtrland, Klout, PeerReach or Kred to check the users score or profile analysis.
The popup also offers to draw a Venn-diagram of followers so you can see how many and which accounts read along with replies. The Venn is drawn by Followerwonk.com.