I personally don't think this just has to do with halo, gamers have become less social all around in my opinion, i play alot of ps3 too and it just seems to be a growing trend, this could also be in part the the gaming age is going down a bit, the ps and the xbox were initially made for the mature gamer, but as most of us know you always want to play what the big kids are playing and companies saw the potential and started marketing to a broader base. Sorry if this doesn't make sense, i'm a little tired right now.