Once subscribed, you’ll get the same updates from Pages that you currently get on your homepage. This functionality is much like that Facebook already offers for regular profiles, where you can subscribe to SMS updates for things like status updates and friend requests from regular user profiles. Unfortunately, some carriers (most notably, T-Mobile) don’t yet work with Facebook Mobile, which makes this feature unavailable to all.
As Nick O’Neill notes, this once again moves Facebook further towards Twitter, who already lets you subscribe to individual user’s updates via SMS. Facebook Pages – or public profiles as they are sometimes called – are part of the social network’s answer to Twitter, and with SMS now enabled, they have duplicated much of the functionality.