Its name is http://openpds.media.mit.edu http://openpds.media.mit.edu, developed at MIT. OpenPDS is a service acting as a middle datastore, between the user (w

Its name is http://openpds.media.mit.edu http://openpds.media.mit.edu, developed at MIT. OpenPDS is a service acting as a middle datastore, between the user (who can even host the service themselves), and the data consumers. The key issue here is to guarantee privacy, by responding with ‘SafeAnswers’ to the queries of external services. It's a WIP, but free and open source.