A users' group (also user's group or user group) is a type of club focused on the use of a particular technology, usually (but not always) computer-related.
Users' groups started in the early days of mainframe computers, as a way to share sometimes hard-won knowledge and useful software, usually written by end users independently of the vendor-supplied programming efforts. SHARE, a user group originated by aerospace industry corporate users of IBM mainframe computers, was founded in 1955 and is the oldest computer user group still active. DECUS, the DEC User's Society, was founded in 1961 and its descendant organization, Connect Worldwide, still operates. The Computer Measurement Group (CMG) was founded in 1974 by systems professionals with a common interest in (mainframe) capacity management, and continues today with a much broader mission. The first UNIX users' group organized in 1978.
Users' groups began to proliferate with the microcomputer revolution of the late 1970s and early 1980s as hobbyists united to help each other with programming and configuration and use of hardware and software. Especially prior to the emergence of the World Wide Web, obtaining technical assistance with computers was often onerous, while computer clubs would gladly provide free technical support. Users' groups today continue to provide "real life" opportunities for learning from the shared experience of the members and may provide other functions such as a newsletter, group purchasing opportunities, tours of facilities, or speakers at group meetings.
A users' group may provide its members (and sometimes the general public as well) with one or more of the following services:
annual or less frequent users conferences
a library of media or tools
a software archive
an online presence such as a dial-up BBS or Internet website
Users' groups may be organized around a particular brand of current hardware (IBM, Macintosh) or current software and operating systems (Linux, Microsoft Windows, Clipper), or more rarely may be dedicated to obsolescent systems or historical computers, for example Apple II, PDP-11, Osborne. An example of an early user group is the Apple User Group Connection.