How and why did the U.S. commercial Internet access market structure evolve during its first decade? Commercial Internet access market structure arose from a propitious combination of inherited market structures from communications and computing, where a variety of firms already flourished and entrepreneurial norms prevailed. This setting nurtured innovative behavior across such key features as pricing, operational practices, and geographic coverage. Inherited regulatory decisions in communications markets had a nurturing effect on innovative activity. On-going regulatory decisions also shaped the market’s evolution, sometimes nurturing innovation and sometimes not. This narrative and analysis informs conjectures about several unique features of U.S. market structure and innovative behavior. It also informs policy debates today about the role of regulation in nurturing or discouraging innovation behavior.