Since the beginning of Google+ itself, the service has required as part of its registration process that users fill out their real names in order to create a profile. Since the beginning of Google+ itself, people have found various ways to skirt this requirement, Google has added support for 'established' pseudonyms, and dropped the real name requirement for Google+ pages.
A lot of this, it seemed, was an effort to reign in the anonymous hate speech and trolling rampant on things like, I don't know, YouTube. Today, though, Google finally gave up - you can now register on Google+ with any name you want, and go back to leaving nastigrams on cat videos as MeatFartMachine666 without that whole "identifying yourself" thing getting in the way.
A lot of the reason behind this change is almost undoubtedly owed to the rather strong online backlash to revelations of US spying programs and the increasing public awareness of internet surveillance around the world. As such, "online pseudonym" has become more synonymous with "privacy protection" than it has "excuse to be a jerk," and Google is almost definitely responding to that evolving connotation.
You can see the official announcement on the Google+... Google+ page, here.