Some if not all of this stems from the Amazon case where they had privately owned companies with Amazon signs for distribution centers. Amazon argued that since they were not the owner of the distribution centers that they should not be have to pay sales tax in that state but unfortunately lost in court.
This ruling has created a cash grab by states where if you have a retail location, have done a trade show, have an affiliate program and a host of other things, it can cause you to be liable to collect sales tax in that state.
More and more states are changing the Nexus laws so they can reap the benefit of sales taxes to their states.
This is just one scenario and just the tip of the iceberg to the complex nexus laws. I think we'll be seeing sales tax being collected online for many states by online vendors where the company appears to have no physical presence in that state but is associated due to a trade show or affiliate.
hoog