Nothing happened to him. He has been in the top sides of the French league for his entire career, was in Dominech 30 man squad ahead of the world cup. Solid left winger, and a great signing for Newcastle...
This might be good for us too. He will get Premier League experience which can be useful if we are to sign him later, because we could need a good left winger, and Ferguson perfers to sign proven Premier League players. Newcastle might not even get a option to buy later, they are not such a big club. I guess Ben Arfa is best in a 4-4-2, does not fit as good Deschamps 4-3-3, and that might be the reason he is moving on.