[adv] What's a Link Worth, Anyway? | Threadwatch.org:
"The quality of the traffic is just as important as the quantity. For instance, let's assume that the target page is part of an e-commerce site. If the linking page receives visits from affluent online shoppers that are likely to convert into sales or leads, this traffic will be quite valuable to the target page. Conversely, if the traffic to the linking page is mostly made up of visitors looking for freebies or warez, then this traffic may be virtually worthless to the target site."