I don't think it's a scam, but reading the FAQ I find this:
Quote
Who will have access to my data?
Authorized third-party companies responsible for data collection, storage, and processing will have access to your study data, including contact information, so they can communicate with you during the study if needed.
My translation from corporate-speak to English is "we'll give your data to anyone we want." And I saw nothing that says they won't sell your data.