[WayneDB]

Synology is doing good things in this area. They offer a "private cloud" backup and file-sharing solution, served from a (linux based) NAS, with client programs for Mac, Windows, Android and iOS. I have a home/small office model and I love it.

http://www.synology.com/dsm/home_file_sharing_cloud_station....

[jacquesm]

I have one of these and I can highly recommend it.

Maximum capacity is 96T, that should be enough for most home servers.