Computer "user groups" began to be created in the early days of computers, with both mainframes and minicomputers having user groups. Some of these user groups include:
- IBM SHARE for mainframes
- Digital Equipment Computer Users' Society (DECUS) for DEC computers
One of the things often done at computer user groups was sharing of software. Often the software shared were public domain. Weakness of this system was that the software can easily be made proprietary. For example, it was reported that Bill Gates copied a lot of the code of Altair BASIC from a version of BASIC from the DECUS user group. Later the copyleft scheme implemented by the GNU General Public License was devised by the FSF to resolve this problem.