Mixx is a new social news site that recently launched an invitation-only beta. The service looks and works a lot like Digg, and even has a four-letter name that looks like someone meant to type three letters but didn't lift their hand from the keyboard in time.

While Mixx obviously doesn't have the kind of enormous user base that makes Digg work so well, the site does have a nice clean interface and a few nifty features. For example, Mixx adds a personal home page. You can select specific areas of interest like news, politics, or technology. When you login to Mixx, you'll be greeted with a start page showing the top user-submitted stories in each of those categories. If you'd prefer, you can still browse each of category page individually.

Mixx has separate tabs for popular pictures, videos, or stories. But while you can see thumbnails of popular images, there's no thumbnail preview for videos, which is a little frustrating.

Another nice Mixx feature is the ability to create private groups. You can submit links that only members of your group will be able to see or vote on.