StumbleUpon, the service that lets you find and recommend interesting sites, works mostly by using a plugin for your browser (Internet Explorer and Firefox). StumbleUpon updated their plugin, by integrating their metadata into search results from Google and Yahoo.
If you enable that option, you'll see a rating (from one star to
three five stars), a link to reviews and the topic of the site. While the topic may be obvious (in the example from the screenshot), the rating and the reviews are useful to decide if the information from that page is valid, reliable, or just to see what others people think about a site. I'm not suggesting that "the voice of the crowd" should be followed, but it's always interesting to see other opinions.