The way I see it, if an Affiliate signs up and doesn't send any traffic at all or doesn't seem to be putting any time into the sites, it can look bad to the sponsor. There are people out there who will put up a particular url, say it's theirs and register just to get some free porn to jerk off to. Pathetic yes, but it does happen.

So if someone signs up and doesn't even remotely attempt to make sales after say...4 months, delete them.

However, if they're making sales - even if it isn't that many - they are still generating revenue and shouldn't be deleted. That would be counterproductive for everyone obviously.

We all know some sites sell better than others. Some of us can sell certain niches better than others. But if a site doesn't sell for you, eventually you're not going to put that much effort into promoting them anymore, are you?

If an Affiliate is sending even a small amount of hits a month, I say keep them on board. Even if they make 2 or 3 sales a year they still helped you sell your site.

My 2 cents