OK, we have been waiting on this one to go down. And my wife read up on it a bit tonight. The ruling has some spots that are pretty narrow. Other states can't just do what they wish right now. I think this ruling was specific to SD and some of the laws they have in place. But it will pave the way for others OR for a move by the feds to streamline the process. As far as the current ruling, it does not kick in until you do $100K worth of sales or 200 transactions in SD.
As this goes forward I'm hoping they keep those type of thresholds. Because I have a pretty decent presence on eBay currently, but I can't afford to deal with this AND keep my prices down. And if the marketplaces do it for me, their fees will go up. Small businesses might be able to absorb costs OK. But micro businesses and cottage business likely can't. The feds already want 1/3 of what you make and you have to claw, scratch, and dig to not have them take it off your gross. It's pretty nuts and sometimes I wonder if it's worth bothering with. And things like can certainly push it over the "not worth my time" threshold.