This is old news by now, but fresh on the heels of firing its Connecticut affiliates, Amazon just terminated its California affiliates program in protest over the new state law requiring it to collect sales taxes on purchases.
The law may be fair or unfair, but Amazon could have easily complied, as it does reluctantly for New York. Perhaps Amazon already wanted to get a bunch of affiliates off its books anyways and this provides a good excuse. But the company is just being childish by lashing out in this manner.
At any rate, the business impact of firing the California affiliates is most likely minimal for Amazon, or else it would have hung on to them, as it has been doing with the New York affiliates.