Backup on a peer-to-peer network is a rich field of research: several protocols have been proposed, for example [Cox etal., 2002], [Bhagwan etal., 2004], [Lillibridge etal., 2003], with different properties, or focusing on different aspects (security, churn, etc...); research has also focused on distributed trust systems ([Cox and Noble, 2003], [Stocco etal., 2004], etc..) to decide which partners to use, or on the maintenance of replica ([Weatherspoon etal., 2005], [Tati and Voelker, 2006], [Wu etal., 2008],...) in the presence of high churn. However, none of these systems have been implemented and really deployed on a large enough sample of Internet users storing personal data.
On the other hand, some companies are now selling peer-to-peer backup solutions, such as [Ubistorage, 2007] or [Wuala, 2008]. However, these systems are not completely peer-to-peer backup systems: Ubistorage provides a box with a hard-drive, whose content is backuped on other ubistorage boxes; Wuala stores files on their servers, and increases their redondancy using peers. To our knownledge, there is currently no supported open-source software providing a complete peer-to-peer only backup system for personal data.