Paying federal and state income taxes is required for every business, including those operated online, but the payment of sales tax is a hotly debated subject in some state legislatures. Traditionally, all businesses are expected to pay retail sales taxes where applicable under state law. Internet businesses have largely been exempt from this rule in many states unless they also operate a physical -- called "brick and mortar" -- location, but some states have adopted sales tax rules that include Internet-only concerns.