Of the various platforms around, Perkzilla is something I found the most versatile having worked with most of them. Their Co-founder James Cantoni has already committed that he can finish off the integration with Bigmarker today itself. It will then be an automatic thing that free seats, entry tickets, passwords whatever we wish to send on achievement of N number of referrals / points / visits can be done without any manual handling. He has alredy written to support@bigmarker.com offering to do this integration today itself, should they be ready. Perkzilla is very versatile in this viralizing features as well as connecting to other platform features with webhooks, custom autresponder HTML code etc. etc.