Business guy here. Depending on what your product is the approach can vary. For all my projects I try to target the most interested group of users. In some cases I might target linkedin groups, meetups, target specific website forums, etc. In other cases, I've tried the ad approach (fb, google, etc). You can also try direct emailing your user group (depending on where they are) and have them sign up for your product (launchrock).
Although I love HN, the challenge I've found with places like Show HN, reddit/r/startup, betalist is that its sometimes not related to the product I'm selling so a)I'm trying to sell a product to the wrong target market and b)tech sites can often times be an echo chamber and the data you get isn't necessarily quantitative.
Although I love HN, the challenge I've found with places like Show HN, reddit/r/startup, betalist is that its sometimes not related to the product I'm selling so a)I'm trying to sell a product to the wrong target market and b)tech sites can often times be an echo chamber and the data you get isn't necessarily quantitative.