Ben Mezrich — who wrote the book

Facebook users got a real wake-up call this week, according to Mezrich, whose best-selling book was made into the movie "The Social Network."

"We believe that we own our data," he says. "But the reality now, we all know, is that our data is out there for other people."

Facebook COO Sheryl Sandberg tells CNBC, "We're open to regulation," in the wake of the Cambridge Analytica's data-mining scandal.

Facebook users got a real wake-up call this week, according to Ben Mezrich, whose best-selling book was made into the movie "The Social Network."

Trump campaign-linked Cambridge Analytica's data mining from 50 million Facebook profiles brought into focus a fundamental truth, Mezrich told CNBC on Friday. His book "The Accidental Billionaires" was the basis of "The Social Network" blockbuster, which won Aaron Sorkin a best adapted screenplay Oscar.

"Our relationship with Facebook is kind of built on lies a little bit, because we believe that we own our data," Mezrich said in a "Squawk Box" interview. "But the reality now, we all know, is that our data is out there for other people."

The 2 billion-plus active users of Facebook every month need to realize their data and the company's ability to target custom ads are the reasons they get a "free" platform, he said.

"There's nothing free. If you thought Facebook was a free service, now you know that you get to use it but they get to use what you put up there," he said.

"It's not as nefarious as that sounds all the time," Mezrich argued. "Every now and then you get an ad directed at you because they know what you like. That's not necessarily a bad thing."

"But they are also using that data in lots of different ways," he continued. "We just saw one instance where someone was using it to target political stuff at us. And we don't like that as much."

Since the weekend allegations that Cambridge Analytica, which worked with Donald Trump's 2016 presidential election team, misused Facebook data, regulators in the United States and Europe have been demanding answers. And from last Friday to Thursday's close, Facebook shares were slammed nearly 11 percent.

Facebook co-founder and CEO Mark Zuckerberg and COO Sheryl Sandberg — both of whom remained silent for days on the leak — went on an apology tour by midweek.

Following Zuckerberg's lead the day before, Sandberg said in a CNBC interview Thursday, "We're open to regulation. We work with lawmakers all over the world."

Mezrich said he hopes regulators use a "soft touch." There's been "a lot of anger misdirected at Mark," he said, adding that he does not see Facebook going the way of MySpace.

Mezrich said he's working on a movie and book dealing with bitcoin.