You watch TV. Your TV watches back.

Wrapped in a Snuggie, I like to binge on reruns of “The Golden Girls” all by myself. Except I’m not really alone.

Once every few minutes, my TV beams out a report about what's on my screen to Samsung, the company that made it. Chances are, your TV is watching you, too, through a few nosy pixels on the screen.

Ever wondered why TV sets are getting so cheap? Manufacturing efficiency plays a role. But to paraphrase James Carville, it’s the data, stupid. TVs have joined the ranks of websites, apps and credit cards in the lucrative business of harvesting and sharing your information. Americans spend an average of 3 1/2 hours in front of a TV each day, according to eMarketer. Your TV records may not contain sensitive search queries or financial data, but that history is a window to your interests, personality, joys and embarrassments.

And they're grabbing it because, legally speaking, tens of millions of us gave our permission.

Lately I've been on the hunt for what happens to my data behind the cloak of computer code and privacy policies. So I ran an experiment on my own internet-connected Samsung, as well as new "smart TV" models from four of the best-selling brands: Samsung, TCL Roku TV, Vizio and LG.

I set up each smart TV like most people do: by tapping "OK" with the remote to each on-screen prompt. Then using software from Princeton University called the IOT Inspector, I watched how each model transmitted data. Lots went flying from streaming apps and their advertising partners. But even when I switched to a live broadcast signal, I could see each TV sending out reports as often as once per second.

Many TV makers say tracking what we watch helps them provide helpful personalized recommendations. Right, and people read Playboy for the articles. TV tracking is mostly about filling in a missing chunk of data about our lives for advertisers and media companies. I tracked down some of the firms that buy it from TV makers. They told me it makes TVs more like Facebook, where content can be measured and ads can be better targeted and tracked for performance.

And just like on Facebook, things can turn creepy. Data firms use your TV history to link up what you watch with what you do on your phone, tablet and laptop - even what you buy in stores. It's like your TV can unhook itself from the wall and follow you around.

Here’s the truly vexing part: Since 1988, watching TV has been one of the few private activities specifically protected under U.S. law. (Congress passed the Video Privacy Protection Act after reporters published Supreme Court nominee Robert Bork’s video-rental records.) In 2017, the Federal Trade Commission rebuked TV maker Vizio for being deceptive and unfair in tracking customer screens. The FTC told Vizio — and the entire TV industry — to be upfront and to make it so that customers had to opt in.

Don't recall opting in to TV tracking? Me neither. Two and a half years after the FTC took action, new TVs include more small print requiring you to click "agree" when you set them up. But the majority of American smart TVs still have tracking turned on, according to the TV companies.

TVs were supposed to be a privacy regulation success story. Now they're looking more like a cautionary tale.

How does a TV watch you back? Think of it less as a dumb box and more like a 65-inch computer.

Trying to measure TV habits has long challenged the industry. Market research firm Nielsen famously signs up people to panels, but they're just a sample. Streaming services such as Netflix keep meticulous records about what we watch but are limited to their own product.

A decade ago, the arrival of smart TVs with internet connections and apps gave an engineer named Zeev Neumeier a new idea: have the TV itself report on everything that crosses its screen. "We built a better mousetrap," says Neumeier, now the senior vice president of technology at Inscape, the data division of Vizio. It's called "automatic content recognition," or ACR.

Neumeier, whose company is under orders from the FTC to be transparent, was the only industry leader willing to sit down in front of a TV and explain how his company tracks me. (Others, including LG's ACR provider Nielsen and Sony partner Samba TV, wouldn't even answer questions on email.)

Once per second, Neumeier told me, Vizio TVs capture a fingerprint of what's on the screen. It looks like two dozen square bundles of pixels scattered around the screen, which the TV converts into a string of numbers. That string is what the TV beams back to Vizio, along with identifiers for your TV.

Vizio compares the fingerprint to a database of known content - like Shazam for video. The result is a second-by-second log of your TV time, which the firm sells to about 30 different companies.

(Not everything you watch gets included. Vizio doesn't keep track when you're using the Netflix app, at the request of the streaming giant.)

Samsung said its ACR technology also uses fingerprints but declined to be more specific. In my test lab, TVs including the Roku-branded TCL model asked to be logged in with my email address and transmitted snapshots of my entire screen. Good thing I wasn't watching anything more embarrassing than Betty White reruns.

Many of the TV companies say they aren't violating our privacy because ACR data technically isn't "personally identifiable information." TVs, they say, are shared by an entire household.

But the firms do collect, use and share one other important piece of identifying information: your TV's Internet Protocol address. An IP address is your home's identity on the internet, shared across all the gadgets you own (which are also gathering data about you). It's how they link up what you see on TV with the rest of your life.

- - -

ACR data reveals a lot more than what's trending or popular. It's a tool for marketers to build a trail from what you binge to what you buy.

With so much more detail about who's watching what, advertisers can use ACR to better target messages. Samsung and Roku TVs comb the data to identify household interests, and then insert ads based on them right on your TV screen. (That's why those two firms say they don't "sell" our personal information - they just make use of it, instead.) Who knows what judgments they'll make if they see you watch a lot of reality TV, CNBC or both.

Other ACR firms, like Sony's partner Samba TV, use the data to re-target ads you see on TV across your computer and phone. (Smart advertisers also use the data to avoid annoying you by repeating the same ad.)

ACR data also lets marketers match what people watch with other data sources - apps, loyalty cards, you name it - to help measure the effectiveness of ads. They want to know exactly how many Ford ads people saw before they bought one.

It's not always "you" they're after; sometimes it's aggregated, statistical models of people who act or watch TV like you. And placing personalized ads on the TV is still in its early days, ad execs warn.

But just imagine the possibilities in elections. While it's not common yet, using ACR and voter databases, campaigns could know which shows persuadable voters watch most - even when the programs have nothing to do with politics.

How does any of this benefit us? "If you want great TV, then the TV industry needs to monetize itself," says Vizio's Neumeier. "And ACR data allows them to do that in a way that is privacy-compliant and respectful of the user."

With better data, he says, we'll get more-relevant ads and networks will get paid more for their ads - which could lead to better shows and maybe even fewer commercial breaks.

But I'm still not convinced tracking is a good deal for us. Making network ads work more like online ads also could make TV terrible. And it puts one more trove of data about our lives in the hands of companies that could misuse it - or manipulate us.

- - -

How many people would consent to that? According to these companies, the vast majority of us. And unfortunately, that's good enough for the government, too.

When the FTC settled with Vizio in 2017, it said the TV maker had to clearly and conspicuously disclose how it captured TV data.

Neumeier, only partly in jest, calls the opt-in menu for Vizio TVs the achievement he'll tell his grandchildren about. The menu, developed through lengthy negotiation with the FTC, is titled "Viewing Data" and explains how ACR works in a hundred words, packaged into four chunks.

The "Accept" button is preselected, but you do have to press it to continue setup. Declining doesn't deactivate any of the useful functions of the TV.

Today, nearly 90% of Vizio TV owners opt in. Neumeier calls that a "good number." Enough people are saying no to show they understand it, he says - but not enough to indicate people really find the idea distasteful. "You opt in because you generally don't mind, or are in fact happy that your data is helping the TV industry," says Neumeier.

I suspect Vizio owners aren't putting that much thought into it. The implications of ACR took me weeks to unravel, and this is my job. More to the point: Why would so many people say yes when we get so little immediately in return?

Industry consultant Alan Wolk says when his firm TVRev surveyed consumers about ACR in 2017, it didn't find much concern. "The basic attitude was, 'Google tracks everything I do,'" he says. "'If Samsung or Vizio know that I watch 'Blackish' and 'The Tonight Show,' who cares?' If anything, the attitude was, 'Good, maybe my favorite show won't get canceled if they know I am watching.' "

Neumeier and I agree on one thing: Vizio's post-FTC disclosures are clearer than the other TVs I tested, which make you feel like you don't even have a choice - not unlike the terrible default settings on Facebook.

Roku TVs make it impossible to separate ad-tracking from smart-TV functions like show recommendations. Its ACR opt-in menu is titled "A Better Smart TV Experience from Roku," and has "Use this info to enhance TV viewing" pre-checked for you.

"We believe we've been thoughtful in our implementation," says spokeswoman Diane Carlini.

Samsung buries ACR permission under the heading "Terms & Conditions" - a giant red flag for DO NOT READ. "I agree to all" is also preselected. When I set up my own Samsung TV, I didn't even realize I could say "no" to any of this.

Two and a half years after the FTC took action, I can't imagine this is the result that regulators were hoping for. "There isn't a real meeting of the minds here where people are saying let my TV habits be collected," says Justin Brookman, a former FTC official who now directs privacy and technology policy for Consumer Reports.

Companies know we're easily bamboozled by what are called "dark pattern" designs that make you choose things that aren't in your best interest.

You can change your TV's settings after the fact. Many makers bury the settings in out-of-the-way menus such as "Terms and Policy" on Samsung TVs. Consumer Reports offers a detailed model-by-model guide.

Should we really have to read the fine print on an entertainment device? Drawing the privacy line at "consent" puts a lot more power in the hands of companies than consumers. Why not limit some kinds of data collection altogether?

"We enforce the laws that we have," says Kevin Moriarty, who was the FTC's lead attorney on the Vizio case. "The law as we have it is focused on allowing consumers to make decisions about how their data is used."

The FTC hasn't announced any additional actions against TV makers. But it has recommended that Congress enact legislation to give it more tools to protect consumer privacy.

Waiting on Congress to figure out how to protect our privacy feels like a bad rerun.