I'm really surprised http://tent.io http://tent.io has not been mentioned here. Tent is a protocol that allows users to pick and choose a datastore provider fo

I'm really surprised http://tent.io http://tent.io has not been mentioned here. Tent is a protocol that allows users to pick and choose a datastore provider for use with any tent compatible application. The provider can be centralised, on the user's own infrastructure or anywhere in between. Applications can be installed locally (without a dependency on communicating with another server, other than the user's chosen datastore) or hosted on a web server. Users get to choose where (and control how) an application stores their data, and developers don't need to think about infrastructure, user management or authorisation when designing and building their app. The protocol is at v0.3 and is not ready for the mainstream yet, but it's coming, and (for me) has the potential to replace a bunch of web apps I regularly use (think dropbox, gmail, github etc.).