With Networking sites like Myspace, facebook and orkut getting immense popularity, which means that most internet users visit those sites.. (Myspace is the second most visited site after yahoo-comScore data) Which means, most of your prospective visitors also visit one or two of these sites. If you are a webmaster, and frequent DP, chances are you have a few sites, and that you dabble in NICHE sites. Even if you can't get a good serp for your Niche words, what is stopping you from creating a community of the same keyword in say Orkut. And since you are the manager of the community forum, you keep to advertise ur website on the forum landing page. And marketting a community is much easier than marketing a site.. One example is a person who built a very popular forum, and then built a website only based on that forum. At last count he had 1500 email subscribers to his blog.