GamesRadar, Marvel vs Capcom 3 has a relatively unique solution to the problem of habitual online quitters. That is to say: People who quit online matches before they are over. That is to say: Rage quitters. Marvel vs Capcom 3 reportedly tracks players' quitting habits and can detect those who quit frequently. Said players will then be placed in a new matchmaking bracket -- one populated solely by other rage quitters.
In other words, quit all the time and you'll be paired with other players that quit all the time. Shoryuken notes that a similar system was implemented in Tatsunoko vs Capcom. We've contacted Capcom to confirm if such a system is indeed in place for MvC3. Assuming it's true, it's certainly a novel concept, though perhaps a terrifying one for those with unstable internet connections.