Excerpt from a timely Dave Winer reality check (although I assume the Google+ team is also very focused on corporate social networking/customer community communication opportunities)
So now maybe that makes it clear why they want your real name on your Google-Plus accounts, and why they don't want to screw around with corporate presences. Not such a problem for publications like TechCrunch or Mashable, which don't move around a lot of money. But for any business like say an oil company (extreme example), they want to have all kinds of flows hooked up to your Google account.
Google plays a huge role today in defining value in Internet commerce. Google-Plus is their integrated communication system. Over time, it's going to be at the core of everything they do, from auctions, to paying for things with Android phones, to their groupon and yelp clones. They're going everywhere, and this is the system that will tie it all together. So, at the outset, of course they need real identities. That Google-Plus account you're playing with today is going to be your bank account next year.