SAN FRANCISCO — Facebook's top lawyer Colin Stretch says it was unacceptable that a Russian organization linked to the Kremlin targeted Americans with Facebook posts and ads to sow discord in the tense political climate surrounding the 2016 presidential election.

Yet Russian operatives used Facebook exactly the way it was intended: Spreading information farther and faster than a cold virus in a kindergarten classroom, reaching as many as 146 million Americans on Facebook and Instagram.

And that's a wake-up call to Facebook's 2 billion-plus users, who for years have allowed the quiet culling of their personal data in exchange for the free service without much thought to what happens to that data, let alone whether a foreign power could exploit it to stoke outrage over polarizing issues from gay rights to gun rights.

In hearings on Capitol Hill this week, lawmakers showed off some of the ads that Russian operatives bought on Facebook. One called "Being Patriotic" promoted a "Miners for Trump" rally in Pennsylvania, a swing state. Another ad from "Heart of Texas" claimed Hillary Clinton was "despised by the overwhelming majority of American veterans."

"What we’re talking about is a major foreign power with sophistication and ability to involve themselves in a presidential election and sow conflict and discontent all over this country," Sen. Dianne Feinstein (D-Calif.) said during a Senate Intelligence Committee hearing Wednesday. "This is a very big deal."

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Lawmakers pressed Facebook on just how easy it was for Russians to target American users. The answer: Facebook created a multibillion-dollar digital advertising business by allowing marketers to pinpoint exactly whom they want to reach by selecting criteria such as location, demographics, behavior and interests — all information that Facebook collects each time someone logs in.

"Facebook is designed to amplify messages that are extreme and emotional and that's exactly what's happened. Facebook is designed to allow people to send messages to a lot of people for very little money and that's exactly what's happened," says Siva Vaidhyanathan, professor of media studies at the University of Virginia and author of Antisocial Media, an upcoming book on Facebook. "Combine the two and it's a perfect propaganda machine for anyone who wants to distract or disrupt a democratic republic."

Political pressure mounted this week as executives from Facebook, Twitter and Google answered questions on Capitol Hill about election interference by Russians on their platforms. Russia has denied any meddling in the election.

Facebook knows you better

The current political storm has its roots in Facebook's data-obsessed success. The giant social network is constantly hoovering information from what you post there: your age, gender, education and income level, job title, relationship status, hobbies, political leanings, what TV shows and movies you like, what kind of car you drive.

It also tracks which pages you like and the ads you click on, the phone you use and your Internet connection as well as the sites you browse on the Web. It buys information from data brokers that gather detailed information from public records and previous purchases and purchasing behavior, among other things, ranging from the value of your home to whether you carry a balance on your credit card.

When you combine that information with what Facebook already knows about you, it's arguably the most complete consumer snapshot on earth.

"Facebook is collecting more data than anyone except the U.S. government," said Logan Young, a vice president of strategy at BlitzMetrics, a digital marketing company that focuses on Facebook ads.

Just as Facebook tries to show people what they want to see in their news feed, Facebook uses the data it collects to try to show people the kinds of ads that are most relevant to them. For example, a baseball clothing line can target people interested in baseball, not just people who like sports. Or a make-up line for African-American women can target African-American women, instead of all women.

But ad targeting can be abused. The media has uncovered potential misuses of advertising tools including the ability to target people who expressed interest in anti-Semitic topics such as "jew hater" and the ability to exclude specific racial and ethnic groups when placing housing ads. After potential misuses were reported to Facebook, it removed those capabilities.

Facebook first disclosed in September that Russian actors bought ads to meddle in the U.S. election. Among the content created by the Russian propaganda agency was a popular "Blacktivist" account that posted videos of police brutality, publicized rallies and urged black people to "wake up." Another fake account, "Being Patriotic," argued that Black Lives Matter activists who disrespected the American flag should be "immediately shot."

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The campaigns that fooled some activists demonstrated just how effective Facebook advertising can be, even on a relatively small budget.

Facebook estimates that 470 Russian-backed accounts from the Internet Research Agency produced 80,000 posts and bought 3,000 ads on Facebook between January 2015 and August 2017. In all, the Russians spent about $100,000, according to Facebook. About 75% of the ads were targeted broadly at Americans and 25% of the ads were targeted specifically to certain parts of the country.

By targeting key demographic groups in swing states, such as Michigan and Wisconsin, two states that were critical to Trump's election win, the Russians could have swayed public sentiment with a relatively small advertising budget, Young says.

The possibility that a foreign power used Facebook to influence voters has made Americans uneasy. Just 18% of Americans say the amount of data possessed by companies like Facebook is a good thing and 78% see it as a bad thing because of the potential for misuse, an Axios survey found this week.

User ranks keep growing

Yet it's not clear that greater public understanding of how much Facebook knows — and how that information can be used for ill — will turn off users.

Over the years, people have grown accustomed to ads hounding them on Facebook.

Victoria Heckstall, a 26-year-old lifestyle blogger from Newport News, Virginia, says about half the time it's as if Facebook ads read her mind. Through one ad, she bought a facial mask that she's still using, through another she discovered a nearby kickboxing gym where she now has a membership.

"That ad was right on point. I was thinking about trying a new fitness program," Heckstall says. "I still have the membership. It's one of the best investments ever. I am really glad I came across the ad when I did."

That consumer acceptance has helped Facebook build a service that's used by 1.3 billion people every day and a digital advertising business that is second only to Google.

On Wednesday Facebook continued its hot earnings streak, recording its best quarter yet and showing how highly effective Facebook ads are in targeting its users.

The only alternative for consumers would be to delete their accounts. But very few have. For many, having a Facebook account isn't just a convenience, it's a necessity, like having a social security number or a phone number .

Facebook may not charge a fee for its service, says Andrew Keen, but "we pay with our data, with our digital blood."

The author of an upcoming book How to Fix the Future: Staying Human in the Digital Age, Keen says he doesn't have a Facebook account because he's not willing to pay that price.

Follow USA TODAY senior technology writer Jessica Guynn @jguynn