I'm going through this somewhat myself, albeit with a website I released last week. I've started to leave thoughtful comments on blogs that relate (with the website as the author name/url), answering relevant questions on yahoo answers and so on with the website sourced. Marketing feels dirty and unproductive, but it is really something I think I'll just need to get over. At my last job, marketing outnumbered developers 4 to 2. At the time I thought it weird, but I'm beginning to see some reason behind it now. My advice would be to put some serious time into a marketing strategy, and give it a budget even if it's a shoestring.