From Fan History Wiki
In September 2009, the NFL announced it was banning fans from live updating of the games on sites like Facebook and Twitter. The league was also planning to crack down on fans who video taped segments of the game to upload on sites like YouTube. First they would warn fans against this behavior. If the fans did not take corrective action, the league announced that they would try to sue fans.  The league claimed it needed to take these steps to protect their income from exclusive broadcasting of games.