Previewed earlier this year as Facebook Zero, the new mobile site is meant to load faster by simplifying some features while still allowing users to do basic things like read their news feeds, publish status updates and wall posts, and post "Likes" and comments.
Facebook has partnered with 50 carriers in 45 countries access to offer the service for free, even if users don't have an existing data plan with their carrier. People will only pay for data charges when they view photos or when they leave 0.facebook.com to browse other mobile sites.
A quarter of Facebook's last officially announced total of more than 400 million users also access one of the social network's mobile properties. The company is expected to hit the 500 million-user milestone soon. --Mark Walsh