Ozzie, who confirmed that Microsoft is considering letting other companies integrate applications into its Bing search engine.
Is the iPad a PC? Mossberg asked.
"Sure, of course, it is. It's a different form factor of PC," Ballmer said.
Ballmer said the iPad is "a flat device where you can buy a docking station -- you can dock it and start turning it back into a PC," he said.
PCs can also be flat, he continued.
Ballmer was candid about how Microsoft fumbled its strong position in the phone business, which he's now directly overseeing, saying it was the result of poor execution. He told Mossberg that Microsoft's phone business has been overhauled, similar to the way its Windows business was sorted after the Vista debacle, and is better positioned with the new version of the phone platform going on sale this fall.