I trying to build community x, which is kind of a stack exchange for domain y. At the center of this community would be data pertaining to domain y. However, in order to get the data, I need users to upload it. The data would be generated by their use of a product which I can give away for free, whereas my competitors charge about $50 for the product. So, I'm wondering if there is a list of techniques I can use to incentivise users to contribute the data back to the site.
Of course, there are all the common gamification techniques. Any others? For example, since I'm the only place able to give the product away for free, I was thinking about something like charging $25 for it, but if the users upload the data, they are refunded the amount they paid. Not sure this would work though, since once the money has been paid, it might be an out-of-mind-out-of-sight kind of thing and they wouldn't bother sending the data back to the site.