This is the new way to procrastinate online. You need Mozilla Firefox to download it (which is free) and you can access it anytime from your Firefox toolbar. Basically, you just select your interests and when you feel like killing some time click the "Stumble!" icon and it takes you to a random website based on what you like. Interest include: science, religion, arts, hobbies, history, and lots more. They even have a a cat lover selection (which I'm soo in). The websites StumbleUpon automatically directs you to can be anything ranging from random Youtube videos, sales at online stores, inspirational quotes, news stories, flash animations, to interactive media and games. If you like something you can write a review for it, and if you don't you can just stumble to another page!
I think that this has the potential to be good for online businesses because it is increasing traffic on a lot of lesser known sites (especially some of the shopping and news sites.) I have yet to try it, but StumbleUpon even has a social network section. You can make friends and see the pages that each of you liked and disliked. You can even send each other messages and, I think, you can contribute content to different categories. To download, just search StumbleUpon in a Firefox search engine.