@ EaglesEye379
You have remember that Xbox Live members already have an established group of friends in their communities and gamer identities with achievements, and this momentum is carried forward.
I think from the grand perspective this means little, about a third of 360 owners are currently subscribed to XBox Live Gold, membership may fluctuate as it does cost consumers additional money on a regular basis and some of the subscribers may just be RRoD compensated temporary members.
And it's not like there is nobody playing PS3 games online neither. Growth is more easily achieved on the PS3, someone who owns both 360 and PS3, may decide Live isn't worth the cost, yet playing PS3 games online is always a free option if you have internet access.
With regard to communication and multiplayer, Home looks like to allow for way more extensive communication than the 360 ever provided (sharing content, playing chess, bowling, checkers darts, etc with others, war rooms, avatar experessions in combination with voicechat and keyboard support, etc). With regard to multiplayer Resistance 2 seems to take online multi-player to a new level, especially for console standards (8 player co-op campaign, up to 60 players for deathmatch, etc).