I just got a little flurry of adding notices on G+ from friends using their SCA names or other autonyms. Please be aware that these sorts of names are currently grounds for your account being suspended; indeed, right now there are witch hunt conditions on G+, where if someone doesn't like something you've said, especially if you are arguing in favor of G+ allowing autonyms, then they can (and do!) report you to the authorities as suspicious, which will get your account suspended.
This has been a huge controversy, and even made it to
an opinion piece in the NYT site. Just because I'm using an autonym and haven't yet been suspended, please don't assume that it's "OK" to do so. If, however, you're joining the revolution, then by all means.
That said, I think it's a stunningly bad idea to participate in G+[*] with your legal or professional name, for a whole host of reasons.
[* It's funny. I say I hate Facebook, and I've heard more times than I can recall, "Oh, I know what you mean", but not once has anyone actually asked me why I hate Facebook. I think that socializing online under your professional or legal name is like drinking and swimming. Enticing people to socialize with friends, family, schoolmates and coworkers online under their professional and/or legal names is like putting up a big sign "POOL PARTY! PRIZE FOR HIGHEST DIVE! NOW WITH SHALLOWER WATER! ***FREE BEER***!!!"]