For me it is not 100% clear how Datum will collect the data en store it, without FB/Google taking it too.
Now that you say this, I became very curious how they wil collect data before FB/Google takes it.. I read the whitepaper again, but all it explains is how datum encrypts data etc.
Only thing I can imagine is that Datum saves info you post and sells it (if you want) to other parties for cheaper than facebook or google price.