I didn't see anywhere where they said they would pay you to click on the ad. I'm sure they can come up with something to get the user to rely on MSN search more and other search engines less provided they refine their SERP's.
"We'll actually go to users and say instead of us keeping all that ad revenue, we'll actually share some of it back with the user...[who] essentially will get paid, either money or free content or software things that they wouldn't get if they didn't use that search engine."
It sound like incentivizing clicks. But he could be referring to rewarding users for registering with them, and using their various services like MSN Spaces, and hotmail etc.
Nevertheless, it's disheartening to hear Bill Gates phrase something as badly as this.
It's a disappointing statement because it makes him sound out of touch.