"Microsoft will have a first-party offering that is significant," Dworkin said, explaining to developers that the choice to advertise with Microsoft would be theirs.

"We will strongly encourage you to use that first-party offering," he said. "It will be industry-competitive, industry-leading in certain dimensions. But you don't have to use it. You get to make that choice."

Dworkin offered no other details. Microsoft is already in the advertising business on other platforms, including Windows Phones and the Xbox 360, but I believe this is the first confirmation of an ad platform for .

Dworkin outlined several other noteworthy Windows 8 app store features during the session:

For more on the Windows 8 app store, check out , or at the Microsoft's overhauled operating system.