But even though it's a small change on the surface, the clampdown on device-level reporting speaks to the rising demand for accurate device data – and to Facebook's desire to plug any potential leaks from its own device graph.
About 18 months ago, Facebook started letting some app marketers collect data from their mobile install campaigns at the device level. This tracking required marketers and their metrics partners to visit a specific page and sign a document limiting how they can use device-level information.
By agreeing to those terms, the advertiser pledged to keep any device level data for itself and not to share it with third parties. It was a tacit acknowledgement by Facebook that some of that device data belonged to the company buying a campaign. With the latest change, that idea is over.
"There is a philosophical discussion which I think can be had, regarding who owns the data," said Michael Oiknine, CEO of trusted Facebook MMP Apsalar. "Is it the advertiser who paid for the download or retargeting, or is it Facebook?"
It's a power struggle that increasingly has played out between advertisers and their data-management platforms on the one hand, and the top ad platform companies on the other. Google's decision to prevent data-management platforms from firing pixels on Google Display Network may be interpreted in a similar way.
Oiknine continued, "Does the transaction which happens between the advertiser and Facebook by which the advertiser pays a cost-per-click or cost-per-install, does that give them the right to the user-level data? That's a big question, and Facebook has made the decision to say, 'That data is ours.'"