The question that I keep seeing come up is how on earth would they enforce this new tax law?
Yes, it would be (to paraphrase Linda

) "complicated and costly for retailers to install complex tax collection systems", however on top of this it would involve major organization on the behalf of the state governments to track down ALL of the merchants that have affiliates based in NY.
I guess if the payoff is high enough ($50 million), they'll try and find a way...?