No, actually real users. YouTube used to use user names. When they tried to force Google+ integration they gave the option to use your real name or split your account and have two “profiles”. One with your username and one with your G+ name. When G+ was unceremoniously brought to the backyard and old yellered, the G+ profile was changed to your old YouTube username plus a bunch of random numbers. Some time later they fused all profiles, leaving a bunch of people with just a word and random numbers. It can be changed now, I think, but most people don’t bother.