Some would-be users have already been booted off the network for using an identifier that, in Google's judgement, does not qualify.
"By providing your common name, you will be assisting all people you know in finding and creating a connection with the right person online," the company says.
That reasoning falls at the first fence; most people who relate to me in a journalistic context call me Stephen (that's my byline); family and friends almost universally call me Steve. Google+ makes a feature of the ability to maintain distinct "circles" of relationships as we do in life, then ironically denies this with its naming policy.
As senior editor at The Atlantic magazine, Alexis Madrigal, put it, in a recent widely-tweeted article: "the kind of naming policy that Facebook and Google+ have is actually a radical departure from the way identity and speech interact in the real world. They attach identity more strongly to every act of online speech than almost any real world situation does."
The New Zealand government's Identity Verification System (IVS), part of igovt, preserves a consistent "identity credential", but still allows people to log on with different names to different agencies.
In recent online-facilitated political struggles in the Middle East, freedom and life itself have depended on the ability to assume pseudonyms.
Madrigal says if he were to shout slogans against the government in the street of his more democratic nation, few people would identify him.
He's presumably imagining a large US city; it would be less true if I were to do it in Wellington. But the point is well made.
People in "real life" do not always need your name to note and form an opinion on what you say.
Hardly any of us consider ourselves to be the same person we were 20 years ago. We are free to change our identity in all but the narrowest philosophical sense. Even the law will, after seven years, forget many offences we have committed.
Yet a prospective employer armed with images of youthful Facebook indiscretions, can insist we must be the same person as we were then. Already social networks are defining us and claiming to know us, in a way we would never claim to know ourselves.
An argument for consistent naming online can easily be dressed up as an accountability measure that can deter undesirable activities; from illegal acts to the merely devious tactic of expressing support for one's own position under another name, to make one's voice appear louder.
There are desirable outcomes to having a single name, but it is clear what the biggest advantage to Google and Facebook is; the more information they attach to one identity, the bigger, better-defined target you will be for advertising and marketing.
As we all know, assumptions about our tastes can be riddled with errors and oversimplifications. And a lot of us simply don't want to be a target for "targeted marketing".
If you do want someone else to tell you what kind of person you are, you're free to stick to one name online and let all the detritus of your words and deeds down the years adhere to that consistent identity. But let it be a free choice.
Leave us to define our own identity and, if we wish, wear the occasional mask. The spectre of corporations knowing (or thinking they know) more about us than we do is, to me at any rate, disturbing.