User name

A user is a person who uses a computer or network service. Users generally use a system or a software product without the technical expertise required to fully understand it.Power users use advanced features of programs, though they are not necessarily capable of computer programming and system administration.

A user often has a user account and is identified to the system by a username (or user name). Other terms for username include login name, screenname (or screen name), nickname (or nick) and handle, which is derived from the identical Citizen's Band radio term.

Some software products provide services to other systems and have no direct end users.

End users are the ultimate human users (also referred to as operators) of a software product. The term is used to abstract and distinguish those who only use the software from the developers of the system, who enhance the software for end users. In user-centered design, it also distinguishes the software operator from the client who pays for its development and other stakeholders who may not directly use the software, but help establish its requirements. This abstraction is primarily useful in designing the user interface, and refers to a relevant subset of characteristics that most expected users would have in common.

In user-centered design, personas are created to represent the types of users. It is sometimes specified for each persona which types of user interfaces it is comfortable with (due to previous experience or the interface's inherent simplicity), and what technical expertise and degree of knowledge it has in specific fields or disciplines. When few constraints are imposed on the end-user category, especially when designing programs for use by the general public, it is common practice to expect minimal technical expertise or previous training in end users. In this context, graphical user interfaces (GUIs) are usually preferred to command-line interfaces (CLIs) for the sake of usability.

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