Ask HN: Determining Site Valuation (Bankaholic = $15M?)

After hearing about the recent Bankaholic acquisition for around 15 million, and watching my jaw hit the ground, I was wondering if anyone could provide some insight as to how that figure was determined. Last I read, the site was only drawing in around 8,000 uniques monthly - which doesn't seem like that much. I'm just curious because I thought I got a steal on the sale of my last website, and I'm beginning to seriously reconsider.