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!
The flip side of that metaphor, though, is that most of us go to lots of parties without necessarily taking the same identity with us to each party. Further, using people's legal names (if this fiasco demonstrates anything, it's that the concept of a "real" name is kind of a crock) doesn't guarantee better interactions - at the Facebook party I run into objectionable relatives all the time, but it's not really my party and I can't kick them out.
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!