Tweetmeme has been doing that for eons. You can even include it as a chicklet on your article, to encourage more retweets.
See, for example, http://tweetmeme.com/story/767267088/danieltennercom-how-to-...
See, for example, http://tweetmeme.com/story/767267088/danieltennercom-how-to-...
We have a similar chicklet to encourage retweets; it differs in that the colors are completely customizable and it integrates automatically with google analytics. Another one of our widgets shows only the interesting tweets: http://widgets.backtype.com/backtweets?url=http://danieltenn...