I originally went to list this site but it came back as unresponsive. With so many tools around I just moved on. But Louis Gray pointed out that it was back online and listed the reasons why. The TweetMeme service provides the following, right from their blog:
Thus tweetmeme was born, put simply it watches what is going on within twitter and picks up anyone posting links to content. We then track how many other mentions of the same content are made (and how influential they are.) and present them in a simple format.
And because the content that is posted on twitter is of a very wide content we also broadly categorize it, these are broken down into blogs / video / images / audio.
I enjoy the service tremendously and so will you.. If you want to see what is the most talked about sites and links, it is the first palce to go right now. They are taking advantage of the Summize purchase.