I spent about ten minutes on the site, so hardly a domain expert. I’m still confused, too. But as best I can understand, you have the option of storage on S3, Azure, and the like. I assume that with a plug-in/driver, you could store anywhere you like.
But non-local storage does seem to be designed in, because there is text like “if there’s a daemon running rsync in the background, you’re doing it wrong” and “if your UI requires marking folders to be synched/not synched, it’s broken”, so there appears to be an assumption of putting your data elsewhere.
It's like your own personal google drive / dropbox / git repo
It's a content addressable storage system. There's plugins to import or export from various major services like foursquare, twitter, etc. and plugins let you store stuff in S3 or mongo or google cloud storage, etc.
I suppose technically running something like OwnCloud with a plugin to fetch your content (text/photos etc) from the various social networking APIs would look near identical from the outside?
Yeah, that part is confusing. If you can throw local drives at it plus a cloud service or two, and it'll just make backups on the cloud, that's actually pretty interesting. It's not clear if that's what's going on though.
But non-local storage does seem to be designed in, because there is text like “if there’s a daemon running rsync in the background, you’re doing it wrong” and “if your UI requires marking folders to be synched/not synched, it’s broken”, so there appears to be an assumption of putting your data elsewhere.