Considering this game is rated mature (that means for people 17+), that really says something about how many people actually give a crap about the ratings for things...lol
online interactions aren't rated...lol
"Online Interactions Not Rated by the ESRB" - Warns those who intend to play the game online about possible exposure to chat (text, audio, video) or other types of user-generated content (e.g., maps, skins) that have not been considered in the ESRB rating assignment.
Therefore the actual online game itself is rated excepting the interactions with other users.
Honestly the problem with ESRB is that most parents don't take the time to understand what it means. I had a parent of a 5 year old a couple years ago come into the store to return a copy of GTA4 because it made her son violent. She was going to buy him a copy of black ops but I talked her out of it by explaining that it was just as bad of a game for a five year old as GTA4 was. Man that kid was stareing daggers at me by the time the talk was over.
TC is right that parents shouldn't buy this game for young children. I'd say you should be at least 12 years old to play any online games. And the parents should actually TEACH them manners and stuff...
You get all these annoying little brats online because the parents are lazy, they can buy their kid a game then ignore him and let the game raise him.