I just saw this post from Greg Reinacker detailing how to use NewsGator Online to add a rating system for your site's content. When I'm finished with my site's redesign, I'm planning to incorporate this functionality. It's pretty neat. The .NET Guy has already added it to his blog and it seems to work well. The only drawback, IMO, is that for a user to rate your content they need to sign up for a NewsGator Online account.
http://www.rassoc.com/gregr/weblog/archive.aspx?post=741 | Comments
One of the cool free features of the new NewsGator Online is the built-in rating system for content. For every post you read within NewsGator Online, you can give it a rating from 1 to 5 stars, and see the community rating as well:
In the example above, the red stars are my own rating (I liked this post that I wrote, so I gave it a 5!), and the community average rating is shown by the orange (4 in this example). [View the rest of Greg's post here.]