More to the point: it's that long tail of niche communities where people talk about the things that make for good site: searching. In marketing terms, these are

More to the point: it's that long tail of niche communities where people talk about the things that make for good site: searching. In marketing terms, these are extremely qualified leads. Many of them are people looking for reviews for something they're about to buy, or who want to talk about something they bought. It's exactly the kind of impression advertisers want to run an ad on.