A referral program is probably the best method for growth and to decentralize user acquisition outreach.
Anyone running a faucet can give away any amount (ie. 50 cents, $1, $5, $10) and can be judged based on user acquisition #'s. The bottom line measure of success of course is those that can acquire more for less.
BTW Square Cash gave away $1 for each signup.
Also how robust is the proof-of-person algorithm? I know Stellar had issues with their free coin distribution and it turned that people were 'farming' coins with fake social accounts all over the world, especially in developing countries. I think it may be good to make it 2FA with:
1) smartphone: iPhone/Android UNID
2) desktop: a hash of CPU & HD IDs
How robust would the above be? Just curious.
Also in regards to improving fake facebook accounts... there is a startup called Fakeoff that is supposed to help detect fake accounts:
http://www.businessinsider.com/fakeoff-app-weeds-out-fake-facebook-profiles-2014-6