There is a big case against EA Sports for the games NCAA Football and Madden (plus another game or two) claiming that EA violated some sort of antitrust/monopoly law in California and thus could fix prices higher... or something to that effect... read about it here: http://www.easportslitigation.com/ I can't see how it would win, but hey, a few extra bucks in my pocket for those games won't hurt...
Basically it is notifying you that you have the right to pull your name out of the class action for your own purposes, be it that you disagree with the suit, or that you want to bring your own separate charges against EA... my understanding was that you do nothing to stay included, if you were included then you will receive compensation if EA is found guilty...