With a case like this, Lee, you think to think of what kind of webmaster you want to be known as. You are already meeting your contractual obligations, so it has nothing to do with legal anything. And you did try to contact him with is a big plus.

But you could...

a) do nothing
b) redirect traffic to his link via .htaccess or whathaveyou.
c) Send a letter to his address on record telling him to update his link.
d) Same as c), but also say that you are happy to sort out his earnings and pay him for what he should have earned if he contacts you anytime before August 1st.

Obviously you can't run a business for affiliates that don't like to use their linking codes. No one expects you to. But whatever you do here, it may wind up getting posted on a message board. You might just get a burst of nice publicity someday thanking you publicly for being such a sport and paying someone for his affiliate income when you were under no legal obligation to do so.

I had a case once where my assistant joined an affiliate program for me and failed to enter my ePassporte account. My finances were a mess back then so I never noticed that I wasn't getting paid. Several years later the company shifted over to CCBill links. We updated, started getting paid for them via CCBill, and never noticed the prior missing payments.

One day I noticed several hundred dollars of unpaid money in their stats area. When contacted about it, they said it was awaiting for me to enter my ePassporte account. Once I did so it went out during their next payment period.

The website did what was legally required of them and I can't fault them for it. But it sure would have been nice if five years before I had gotten a little note from them saying they had money for me if I'd go update my ePassporte account early. And perhaps year letters after that attempting to make good on their debt to me.

So to this day I continue to have neutral feelings for the affiliate company. They did what was legally required of them and no more. As such, I have no better feelings for them than any other affiliate. Perhaps that was worth the interest they made on my money over those years, but I'm not sure it's how I would want to be known as a businessman.

--Aaron