The U.S. Supreme Court ruled in 1992 that states cannot collect sales tax from an out-of-state retailer unless that retailer has a physical presence, like a warehouse, in that state. But the law in Illinois, and in other states with similar policies, established that some out-of-state retailers with "affiliates" in the state — such as Illinois-based bloggers who collect commission by posting a link to Amazon on their website — have a taxable presence.