"Just provide good content" indeed isn't enough. What we should also be saying is that you shouldn't count on Google's search results to do your marketing for you. It's difficult for Google's search results to "lead" the internet. If something isn't already somewhat popular, it's hard for us to discover it, though we try very hard. What I'd suggest is to try to market your site through more conventional ways without worrying about search engines. If real people demonstrate that they like your site when exposed to it, the ball is in our court, and it's really our fault for not ranking you well enough.
However, if not enough people have been exposed to it, there's still more you need to do on your end.
Send the site along, and I'll see if there are any issues I can tell you about.