Howdy,
On the commute into school this morning on the metro, I read about http://www.stopbadware.org. Apparently, its a website dedicated to providing a database of downloadable apps and what they *actually* do, in comparison to what they "claim" they do. Now you can read up on apps before you download/install them, potentially saving you from needlessly infecting your PC with all sorts of malicious applications.
The site is still in its infancy, but it looks like a promising idea.
Cheers,
The Czar
It's also useful to read the SiteAdvisor blog:
http://blog.siteadvisor.com/
They do regular audits of some of the worst spam hives on the internet, and tips on how to avoid this trash.
They're also working on a browser plugin that will automatically warn you if a site you are visiting is spammy or full of "bad" downloads. It also tells you this while reading google results, which is kind of cool.