"The Supreme Court ruled in 1992 that states cannot compel mail order retailers to collect sales taxes unless they have a "physical presence" in the state, such as a store."
Tell that too Amazon who is fighting against states who are now demanding taxs for sales thru them, the part about the store has just now become very hazy indeed to extend to any sales presence and even distribution points.
The thing about Amazon is that they probably have multiple store houses or business locations. If Amazon had stayed in one state they wouldn't have a problem. The fact they also were an online retailer for multiple physical stores at one time doesn't help that fact.
but there in lies the problem, those physical stores do not belong to Amazon, but Amazon is the ones being forced to collect the taxs.
furthermore a physical store is considered any physical location where product is sold, it does not have to be a full time store, so this would also constitute Flea Markets, Garage sales, and even conventions, since a vendor is physically there selling product.
furthermore Amazon and other online retailers are currently trying to sue states which are demanding taxs to be collected:http://news.cnet.com/8301-13578_3-20021867-38.html