Ok, StumbleUpon has nothing to do with Google PageRank, except for the fact that both are toolbar based and reach millions of users. Like PageRank, StumbleUpon also experiences its flaws.. especially on the Top Stumblers page.
StumbleUpon’s own Top Stumblers page is flawed because some users there have 100,000+ stumbles while others have less than a dozen.
StumbleRank lets users add any Stumbler to their database and then keeps track of the stats of those users, updating twice a day to create an accurate list of the top 100 stumblers and their stats.
Users of StumbleRank can sort the stumbler rankings by any of their activity, pages, photos, videos, fans, and reviews; depending on what criteria is most important to them.
StumbleRank, if it catches on (which is should as users will probably begin adding themselves), could become an efficient marketing tool for finding the most active Stumblers per category.
I’d like to see a search engine added to the site, to search Stumble profiles and user tags for relevant terms, identifying sites they’ve Stumbled and themes they prefer.