Do you promote through Social Networks such as Myspace, Gather and others? If so, tell us which network and how do you promote it (bullentin, chat, forums, etc.).
I have once or twice myself, but I know of a few of our affiliates who promote through myspace by posting links to our offers in groups and leaving comments on band pages with the links as well as bulletins. It seems to do well for them. They don't promote anything that requires the user to buy anything, those typically don't work well with the type of traffic you will receive from Myspace.
I've also heard that Myspace is clamping down hard on affiliate type of pages. Part of their ongoing clean up process due to the bad PR they've been getting. And to add to Jonathan's comment, typically when you try to drive traffic from a 'free' site, conversions are fairly poor because these kinds of visitors aren't coming from an already monitized site.