I think it woulld be pretty neat if you could do /fb status [Your Status Here] /tweet [Your Tweet Here] Then having some green text popping up in the chat telling you who re-tweeteed and who liked your status. That saves people from having multiple windows open. It's a stretch but /fb feed Updates the facebook statusess of your frindes but in the minecraft chat and you can /like /comment Obviously like a facebook inside of minecraft but in the form of a plugin. Think about it before you ridicule it.
This could all be done via commands, however I can't imagine it would be better than having twitter and facebook open in another window. This would basically be a LOT of work to make a command line twitter/fb app.
Not to mention who would want to give their facebook and twitter details to a minecraft server just for the ability to have a more difficult way of posting/tweeting
I think you would need facebook to develop it just like how they develop all their apps. Idk if im right though
You can use FB's API, however if you don't have SSL and SSH it is not recommended to do this since session stealing is easy on an unprotected connection.