Users in a computing context refers to one who uses a computer system. Users may need to identify themselves for the purposes of accounting, security, logging and resource ...
http://en.wikipedia.org/wiki/User_(computing)

Wikipedia provides user pages to facilitate communication among participants in its project to build an encyclopedia. If your username is Example:
http://en.wikipedia.org/wiki/Wikipedia:User_page

Good UI design improves the user experience, helping you meet business goals. We offer user interface (UI) design and usability testing for Web and desktop applications:
http://www.user.com/

The first North American useR! was held at Iowa State University, Ames, Iowa, August 8-10, 2007. It follows on from successful meetings in Vienna, Austria, in 2006 and 2004.
http://www.user2007.org/

noun . 1. a person or thing that uses. 2. one who uses drugs, esp. as an abuser or addict. 3. Computers. a person who uses a computer.
http://dictionary.reference.com/browse/user