With its landmark decision in South Dakota v. Wayfair, Inc., the U.S. Supreme Court changed how states can assess sales tax. Physical presence is no longer the deciding factor of whether your businesses has sales tax nexus.
The new standard, substantial nexus, is ill-defined and being interpreted on a state-by-state basis. This means remote sellers have work to do to see if they need to collect and remit sales tax now and on an ongoing basis.
States are moving forward modifying legislation and tax rules with their own unique interpretation of what constitutes nexus. See the infographic below for where states stand and the issues to watch for.