The web is a large and wonderful place, but it's difficult to track interesting articles you might be missing. Sitesimon cures that problem by recommending sites based on your browsing history.
The service works with a Chrome extension, logging each site visit. As a content discovery engine, it will filter out what you've already seen, and then aggregate new pages and articles you might enjoy. The experience can be private or social, and by default secure pages and known adult sites are not recorded when the extension is enabled. The hook is in being able to see what your friends are seeing, but even using it on private revealed interesting pages.
For us, the Sitesimon did a good job of recommending like-minded pages and didn't repeat content too often. It's currently in beta, but it's open to everyone and free.