Collaborative software, also known as groupware, is application software that integrates work on a single project by several concurrent users at separated workstations (see also Computer supported cooperative work). In its modern form, it was pioneered by Lotus Software with the popular Lotus Notes application running in connection with a Lotus Domino server; some historians argue that groupware was anticipated by earlier monolithic systems like NLS. The wiki software upon which Wikipedia runs evolved from a free software philosophy for similar collaborative applications—without the trade limitations of proprietary software or the social limitation of a hierarchy.