If you think of a social site as a party, the rules you set create the environment. And to be fair to Google what makes Facebook good to a degree is that people are anchored to a real identity — this prevents flame wars and all sorts of other noise. Honestly part of the spam problem on Twitter is the ability to setup a fake profile via robot and start spamming everyone within seconds -- fake IDs also are part of what made MySpace feel like a collection of misfits (not that that in itself is a bad thing, but it doesn't lend itself to marketing to a broader audience).

So yes I'd expect Google to want you to be real -- on the other hand that may give room for Twitter or someone new to do something more interesting. Just don't expect said site to be mainstream if you're using 4chan rules for your party!