As streaming services proliferate, so does the technology that tracks their viewers. AT&T, Roku, and ad giant Publicis, among others, are harvesting viewers’ email addresses and the devices they use to stream content. Privacy advocates are concerned, with Center for Digital Democracy executive director Jeff Chester calling the practice a “digital daisy chain of data-gathering on viewers.” But advertisers find the opportunity to gather the specific data available with streaming services too appealing to pass up.

The New York Times reports that even as “viewers try to shield their information, it is sometimes tracked without their permission and shared with corporate giants like Facebook, Google and Netflix.” As eMarketer analyst Ross Benes puts it, [the viewer] shouldn’t have to read through 80,000 words of legalese when you sign up for a streaming service.”

That’s about to be tested in the coming months when new streaming services from Apple, Disney, NBCUniversal and WarnerMedia launch on “connected televisions and devices from Amazon, Google, Roku and more.” TV networks are eager to move into streaming, to regain advertisers that have moved their dollars there.

Hulu, for example, “tells advertisers like Kroger and Lexus that it can help them target consumers based on age, sex, location, and interests and real world actions — both on and off Hulu … [as well as] measure how an ad performed through partnerships with third-party companies.”

Advertisers’ move to streaming platforms continues to accelerate away from network TV; Magna reported that they are “bolstering their spending by 39 percent, to $3.8 billion.”

Streaming platforms are upping the ante, with Roku, which “draws more revenue from advertising and related business than from sales of its streaming players,” paying $150 million for Dataxu, which “helps advertisers automate campaign placement online.” AT&T’s Xandr, its advertising and analytics unit, acquired Clypd, which “can send targeted ads to multiple devices in a single household.”

A Princeton University/University of Chicago study revealed that “some streaming channels on Roku and Amazon Fire TV [are] contacting more than 60 separate trackers, including some owned by Google and Facebook.” When the researchers activated Roku’s “limit and tracking” feature, intended to rein in the amount of data shared, Roku in fact “sent information to more trackers than when the function was turned off.”

Likewise, activating Amazon Fire TV Stick’s “disable interest ads” feature “made little difference in the number of device serial numbers and other identifiers that were sent to trackers.” Privacy advocates also pointed out that Vizio and SambaTV stand accused of selling TV set data without the owner’s “knowledge or consent.”

A Northeastern University/Imperial College London study confirmed, “Roku and Amazon Fire TV, along with smart TVs from manufacturers like LG and Samsung, were sharing viewer data with Netflix and other advertisers, even when the devices were not configured with Netflix accounts.”