A user is an agent, often a human agent (end-user) instead of a software agent, who uses a computer or network service.
A user is an agent, either a human agent (end-user) or software agent, who uses a computer or network service. A user often has a user account and is identified by a username (also user name), screen name (also screenname), nickname (also nick), or handle. In UX a user is most of the time a real person.
Questions having the users tag regards user satisfaction and task completion capability within the field of User Experience.
Referencs: http://en.wikipedia.org/wiki/User_(computing)
