Ask: Anyone have experience getting data from users? (/Google Places)

So, I'm starting to work on a new side project that is essentially an extension of what you would think of a review site (but for a specific niche). I would love to use something like Google Places to allow users to find their points of interest right from the start, but I really don't want to end up tied that hard to their service. I can't copy their data obviously, but I'd really like to...

I was considering offering up a gift card lottery for people who entered data, but I'm not sure if that would be enough incentive to find addresses,phone numbers, etc as a first step in this process.

Am I worrying too much about being strapped to an API like google places?