Facebook today announced that it's serving up to 250 million mobile users, via their native mobile app for iPhone, Android, WebOS, and other app platforms.
Also, Facebook announced that it's merging touch.facebook.com and m.facebook.com into the same site. Up until now Facebook has two versions of its mobile site: "users on smartphones like Android and iPhones have been directed to touch.facebook.com," and "users accessing the site from a featurephones" would be directed to m.facebook.com." But no more!
Facebook Head of Mobile Products Erick Tseng explains that "up until now having two versions of Facebook's mobile website has led to issues, because the site's engineers would have to rebuild the same features twice, leading the two sites to rarely reach feature parity. Now Facebook has launched a new framework based on XHP, Javelin, and WURFL that uses the same underlying codebase, while tweaking UI elements on the fly depending on what device you're accessing the site from."
In other words, Facebook's engineers only have to implement a feature once on their backend, and if your phone supports, it'll show up. In addition to paying attention to a phone's hardware capabilities (if your phone doesn't support location, you won't be able to use Places), Facebook is also optimizing graphics on the fly.