Ask HN: Ideas for Surveying?

I'm working on validating an idea for a project. As part of that validation I need to learn about my potential users. I thought that surveying them would indeed be a good idea, but it's proving challenging to get responses! I've read a lot about driving traffic to a landing page via, say, Ad Words and FB ads, collecting email addresses, and then surveying that population. I'm wondering if anyone has had success with these techniques? Are there any other good resources you commonly use when trying to survey or when trying to find populations to survey about an idea?