Referral campaign is good for growing community in all social media.
The referral program is certainly very good, but I don't like projects where she comes to the fore and all work is to attract new users.
The referral system is very important for the present, I support the project where the referral system is included.
I think all this is superfluous, referral system for the exchange I like, but in general I do not like projects that use referral system, they remind me of pyramids.