A little trippy
Stumble Upon had/has a good idea but on occasion seems poorly executed.
The basic concept is that you sign up for an account and register your likes and dislikes. Based on that the stumbleupon engine finds websites you might be interested. The down side to this is that everyone an their mothers can recommend websites so it's generally used as free advertising, though they try to weed out spam sites.Your thumbs up thumbs down ratings are supposed to be calculated and if you don't like a site then they look at other users who like sites you like and send you to one of those. I suppose im my case I'm in a loose loose situation since I think most of the internet is crap.
The two biggest problems with stumble upon is that people like to recommend sites that link you directly to streaming video, flash animation or quicktime movies which if you have a slow connection can really muddle up the works. I have cable internet and everytime one of these loads my computer slows down then this load annoying song or sound effects come out of my computer. People also like to link to specific pages on websites instead of linking to the main page itself and let people go from there.
The second problem is that I doubt the effectiveness of the stumble upon engine. On several occasion it'll send me to pages I already gave a thumbs down to or pages that I obviously have no interest in.
As is my belief with most websites like this, where user input is the key, they need to develop a regulatory system that checks and balances itself automatically (something like I designed some years ago but fail to launch myself). If stumble upon could do a better job of cross referencing likes dislikes and prevent repeated sites and site themes from popping up it would be lovely. Since it's not and like to send me to pages I hate I'll continue to use stumble upon as my number one source for finding bad webpages.