2. Online retailers must track sales levels and tax law changes in all states where they do business.
This online sales tax has not been implemented in all states, so it will be important for online retailers to track these changes. And these retailers will want to pay attention to the transaction levels (dollars and sales volume) that require small business to pay state tax across state lines.
For example, the Supreme Court ruling said that an online retailer has to pay South Dakota sales tax if it reaches 200 taxable sales in a calendar year, or $100,000 in gross income from customers in that state. Many states are already adopting the South Dakota benchmark model.