In the USA we have has a long standing issue with where sales taxes can be charged for Internet and mail order purchases. The US Supreme Court has ruled that taxes do not have to be charged unless a company has a physical presence in a state, which is called nexus. That has always meant a building, office or an employee living in the state.
Due to the greedy nature of politicians, several states have illegally changed the meaning of nexus to include affiliates, even though affiliates are not employees--they are independent contractors. Independent contractors are not part of a nexus. This started with the state of New York, which already charges the highest tax rates in the country. Amazon has been battling them in court for some time.
This is a big issue for Amazon and all Internet companies. It is not just a sales tax issue. If a state can legally force a company to collect sales tax for sales in that state, the state also has the right to audit the seller's books at any time they desire. That could cripple most companies if they must give 50 states access to their bookkeeping at any time that a state demands it.
Sales taxes in the USA are charged very erratically. A state, city and county can each charge a tax. If an online retailer had to keep track of all of the appropriate taxes to charge, the retailer would have to manage over 25,000 different tax jurisdictions. At a simplified level, a retailer would have to keep track of and make payments to about 5,000 tax jurisdictions.
If Amazon loses their legal case with the state of New York, the consequences are serous for everyone who sells products online in the USA. If that happens, the Congress would have an excuse to change the law so that online retailers could charge a flat tax (same rate for any purchase), which would be paid to the Federal government and they would dole it out to the states.
The lame excuse that I hear from politicians is that local business must collect sales tax, but online stores in another state do not. They claim that this puts the local stores at a competitive disadvantage, but they fail to take into account that online retailers have to pay for shipping costs, which sometimes can exceed the sales tax. Charging sales tax on top of shipping costs will put online stores at a disadvantage.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." -- Benjamin Franklin