They alredy extract the most popular posts http://www.tumblr.com/popular/top http://www.tumblr.com/popular/top I'm sure they have no problems to know which blo

They alredy extract the most popular posts http://www.tumblr.com/popular/top http://www.tumblr.com/popular/top I'm sure they have no problems to know which blog is the most popular (page views, number of "reblogs"...)