I've launched my first 'coming soon' startup Poucher(http://poucherapp.com) and like crazy going through all the social networking sites and reading Entrepreneur.com, Inc for marketing tricks and growth hacks.
I have been trying to analyze the way things work at Internet and honest no marketing channel what so ever has been as effective as Hacker News. One thing that surprised me more than anything was the diversity and how global the HN users are. The feedbacks I've received made me really happy because me and another friend of mine currently trying to respond every question being asked and almost personally thanking everyone on Twitter (@poucherapp) following us.
For future start-up founders, coming from a founder to be, do trust HN community as they'll reward you really well when your product is genuinely interesting.
PS on post: Would love if you could share your feedbacks