in an extract from D5 Conference by Wall street journal I read:
I think there's going to be tremendous revolution, you know, in the experiences of the post-PC devices. Now, the question is how much to do in the PCs. And I think I'm sure Microsoft is ㅡ we're working on some really cool stuff, but some of it has to be tempered a little bit. Because you do have, you know, these tens of millions, in our case, or hundreds of millions in Bill's case, users that are familiar with something that. (the rest omitted)
I don't understand this part in bold. Please explain this sentence's meaning.