From Claire Atkinson, writing for the NY Post:
The company [Apple] is willing to share details on who its viewers are, what they watch and when they watch it to entice broadcast networks and others to go along with the service, sources said.
“They’re allowing a lot more decision-making by the content owner,” said one source familiar with the talks, adding that Apple has told potential partners, “It’s up to you, whatever you guys want to do.”
Apple has always been quite careful to state that they're in the product sales business and not the customer data sales business, so I can see where this kind of report would come as a surprise. Except it's not a surprise. Anyone using Netflix, HBO, Hulu or countless other services on Apple TV (or iOS devices) has already shared their viewing data with those providers. Apple doesn't even necessarily see it. You launch the Netflix "app" on your Apple TV, login to Netflix and, boom, you see your viewing history.
Certainly it's good to be aware of who has data about your viewing (and other) habits, but it's also good to be aware that this is nothing necessarily new for content you stream via Apple TV (or any other device).