There were a lot of discussions in shareware community about Windows Marketplace, and how it would push every non-Digital River/eSellerate (they were payment providers in Marketplace) registration service out of business back in the days when Vista was known as Longhorn. People were preparing for crazy code signing "Design for Windows"-like schemes, because it seemed like Marketplace would be as big as AppStore today.

Well, Windows Marketplace failed. (I think there's still an icon for it in Windows Start menu?)