For awhile now, Amazon has been fighting the battle over the collection of sales tax. The simple version goes something like this. The rule up until now has been that if you don’t have a physical presence in a state, then a retailer does not have to charge sales tax when shipping to that state.
Now, some states are saying that having affiliates in a state, is equal to having a physical presence. One by one, states have been enacting this new law and one by one, Amazon has been canceling affiliate deals with people in those states.