Quoted from goatdan:

States are working to close loopholes and assess sales tax on all interstate trade. Before, machine purchases were able to work through a legal loophole. The loophole was closed after the show last year.
Well, mostly. The problem is States have basically started passing laws stating that out of state businesses need to comply with sales tax code in the state (and sometimes even local area), but the onus is on the individual companies that have not been informed by those states of the change directly, nor is there a simple way set up for small businesses to do it properly.
At some point, a case is going to end up at the Supreme Court about this placing an undue burden on interstate trade, and the companies should win it over the states. Until then, it's a ton of confusion.
By the way, I feel compelled to add that I think that people shouldn't be able to avoid taxes by buying online. I also do think a lot of people weren't claiming use tax. But... This is not the way to do it.
Because of this, the perception is there is an added cost to the purchase of machines this year that wasn't there before, thus adding to the depressed market.
Oh, and to be clear, I think the law changed officially last year, but it was after the show so it did not affect us.