1. A commercial user. One who is paying real money for his computer usage.
2. A non-hacker. Someone using the system for an explicit purpose (a research project, a course, etc.) other than pure exploration. See user. Hackers who are also students may also be real users. “I need this fixed so I can do a problem set. I'm not complaining out of randomness, but as a real user.” See also luser.