In 2012 Google+ required that anyone signing up had to use their real name but that is something that Google has eliminated.
When Google first started, it wanted to be a different social network. It wanted to be a place where real people interact by using their real names but it looks like that has been something that has prevented it from being as popular as Facebook and Twitter.
Now, Google has thrown in the towel for not letting their users use their real name when signing up and they have even apologized for it. Time will tell if this move will help Google+ move up in popularity but we will just have to wait and see what happens.