So far you've extrapolated everything from getting to the front page of HN once, but the more you do that the more their software learns who's helping you with upvotes even as you wear out your welcome in the community. That's not sustainable.

I think you could convince 13 people amongst a group of 15,863 to buy just about anything and that doesn't really prove demand either.

What would be sustainable is finding something that still delivers registrations/customers/money next week when your HN posts are unpopular and it's all tapped out. Somewhere that can actually deliver on the 10x more traffic you aspire to have next and thus worth optimizing your sales funnels for.