Topsy
Via wakoopa.com on November 19, 2009
twitter search engine that specializes in presenting search results based on retweeting. On the search results page they give a list of most frequent authors as well as a list of items that have been most frequently retweeted. At the moment, they say, it is limited to searching twitter. One assumes that means they expect to expand beyond twitter at some point. It came out of private beta late spring 2009.
Meanwhile, on Twitter...