It is not news that tax authorities are looking for ways to tax the digital economy. What is constantly evolving is how they are doing it. The latest initiative at the state level involves the digital advertising tax (DAT), with Maryland leading the pack. Despite being a frontrunner, Maryland is certainly not alone: seven other states have introduced proposals similar to Maryland’s DAT, and four states have presented related measures.1 These proposals, although they vary in details, were launched by policymakers from both parties.2 Given the recent popularity of DAT among legislators, this issue brief first reviews key features of Maryland’s DAT that several other states have referenced. It then discusses the main arguments against the DAT, key reasons to support it, and trends to watch for as developments unfold.