This is the way to attract more people form any group.
I am actually trying to figure out how to do a referral link. You share a link to POW and if someone joins and starts spending/earning, you receive XEC. But it needs to be well thought out so it can't be gamed.
I think the best way to attract users to POW now is through referral bonus. Existing users will earn or rewarded XEC for their invites.