Gabriel Weinberg (Duck Duck Go founder) wrote a summary of his experience using Reddit Ads, which he found to be effective: http://www.gabrielweinberg.com/blog/

Gabriel Weinberg (Duck Duck Go founder) wrote a summary of his experience using Reddit Ads, which he found to be effective: http://www.gabrielweinberg.com/blog/2010/03/my-duck-duck-go-reddit-ad-by-the-numbers.html http://www.gabrielweinberg.com/blog/2010/03/my-duck-duck-go-... A couple of key points from the post: "My ad ran for 13 days, from 3/7 to 3/20. It cost $650, and I spent $50 per day. In total it had 1,288,378 impressions (282,732 uniques) and yielded 20,700 clicks (18,420 uniques)." "Redditors actually try out your site. 3c per unique visitor is pretty good in and of itself, but it's all worthless unless they actually try out your site. For example, you can get 5c unique visitors from StumbleUpon (presumably in a similar demographic), but StumbleUpon visitors never would try out my sites. Reddit visitors did try out Duck Duck Go."