Hello! I've been thinking of making a site like tremorgames, where people can come and do surveys and get keys for their games. I've learned a plenty about keyword research and SEO on this site and finally have the confidence to set up my own website. But the thing is, how do I get surveys on my website and fit them with a virtual currency tag? I.e, I want the visitors to complete surveys and rack up credits on my site. After which they get to redeem stuff. Also, is this very vulnerable to malicious hack attempts?