ownCloud is an open-source software suite that provides a location-independent storage area for data (cloud storage).
ownCloud is an open-source software suite that provides a location-independent storage area for data (cloud storage). The project was launched to create a free alternative to commercial cloud providers. In contrast to commercial storage services, ownCloud can be installed on a private server at no additional cost.
The project is based on PHP and a SQLite, MySQL or PostgreSQL database, so ownCloud can run on all platforms that meet these requirements. ownCloud can be operated via a web interface and is thus not tied to a particular operating system. However, native applications, such as File Manager or Group Wares can interact with ownCloud via an interface and provide data and files locally.
More information available on the project's homepage and on Wikipedia.