StumbleUpon 5

I'm amazed how smart people are. StumbleUpon is brilliant. It's one of these neat, social tools that epitomize the whole "web 2.0" movement, and is a great way to discover new Web sites based on stuff you like. The whole key to it is a Firefox extension in your browser that allows you to indicate what web pages you like as you search the web. So it's distributed... this is a big deal, as it goes with you - it doesn't force you go to any destination web site to share your opinion. The more you rate, the more accurate the page recommendations are for you, and you can be matched up with other people who like other stuff. It's cool. I'd love to see RIA learn a thing or two from these guys about extending it's service beyond the site itself - maybe into the browser, and at least into blogs and personal web sites and the like. Up there with Last.FM as the single coolest service that I've seen in the last few months.