Sure, there’s a “Popular On Netflix” category on the streaming service, but are those actually the most-watched Netflix videos? For years, only Netflix has known how many of its users were watching which videos — and the company has not been eager to share that information. But the folks at Nielsen reportedly are going to start collecting ratings data for Netflix and Amazon videos, pulling back that curtain of secrecy.

This is according to the Wall Street Journal, which reports that the Nielsen streaming ratings will begin next month. Since it won’t have access to data directly from Netflix, Nielsen will sample audio content of streamed movies and shows to determine which titles are being watched.

The ratings won’t initially be made public, and content companies will — at first — only be able to see data for their own shows and movies. Eventually, Nielsen will make ratings for more content available to its subscribers, meaning the numbers will inevitably make its way to the rest of us.

While ratings data may hold some curiosity for Netflix users, the folks with the most interest in the Nielsen numbers would be the content companies that license their videos to Netflix.

Many studios license their content in bundles to services like Netflix and Amazon Prime, so if the Nielsen ratings show that a certain show is particularly popular, the studio could use this info to get a higher fee for all of its content when it comes time to renew the license.

Likewise, people associated with popular shows — actors, producers, writers, directors — might be able to make a case for a better deal from the studio.

Of course, if a show isn’t popular on Netflix — or if the data shows that Netflix users have wide-ranging interests and that individual pieces of content aren’t as important as the entirety of the library — the ratings wouldn’t be of much use to the content companies.

The data could also be used to compare what’s popular online vs. what works on pay-TV, and whether or not streaming services are cannibalizing viewership on cable.

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