Google+--;
Shame on me for thinking Google would take a different tack on this.
http://www.zdnet.com/blog/violetblue/google-plus-deleting-accounts-en-masse-no-clear-answers/567
The relevant part of their ToS states: "In order to access certain Services, you may be required to provide information about yourself (such as identification or contact details) as part of the registration process for the Service, or as part of your continued use of the Services. You agree that any registration information you give to Google will always be accurate, correct and up to date."
This does NOT say that you must register using the name on your birth certificate or government ID, etc. If you are known friends or fans by a name other than your given name then that is still an accurate, correct name.
They want celebs on Google plus, but are Google going to force Lady Gaga to register as Stefani Germanotta? Unlikely. I'm pretty sure this guy's name isn't listed on his driver's license as $0.50 either: https://plus.google.com/114809488257853535663/
EDIT:
The Google+ Content Policy also addresses the name issue, using different language: "To help fight spam and prevent fake profiles, use the name your friends, family or co-workers usually call you. For example, if your full legal name is Charles Jones Jr. but you normally use Chuck Jones or Junior Jones, either of those would be acceptable"
Some more good info on the topic here:
http://infotrope.net/2011/07/22/ive-been-suspended-from-google-plus/
http://infotrope.net/2011/07/24/more-comments-on-google-plus-and-names/
And a data collection effort for people who have had their profiles suspended, here:
https://spreadsheets.google.com/spreadsheet/viewform?formkey=dFZHSEZ6ZURPQkpyTldMMXFFNkJrU0E6MQ#gid=0
EDIT+:
Another good article on this subject:
http://nakedsecurity.sophos.com/2011/07/27/google-misses-an-opportunity-privacy-is-an-important-part-of-openness/
There is yet another page at Google explaining their profile name policy and this one is more specific than the other two I've seen, stating that you must use the name you go by "in daily life".
http://www.google.com/support/+/bin/answer.py?hl=en&answer=1228271

