If it was Facebook you should know by the message. But looking at the number I believe it is.
Last night my brother commented my wall (he wants my old cell) and the number the text alert came from is 32665111. Message read "User has commented on your wall: Users message blah blah blah...
When you update your status through texts, you send a message to 32665 which is Facebooks short code. As long as your mobile settings are set, your status is updated for your profile.
Edit update: Forgot I had my old phone in my purse.
Additional FB messages from last week are on there. All came from the following codes:
32665106 (a few times as it was from the same friend commenting on a few of my photos)