I joined Facebook in the spring of 2005 with the first email address I ever had. I still remember the photo I chose: me in a silver cocktail dress I spent too much of my summer lifeguarding money on. Facebook was a constant throughout college: There was the thrill of the new friend request, the agony of an unflattering tagged photo, the titillation of new-crush “Facebook stalking.” The site was a phone directory, a photo album and a way to invite people to parties. It was social ephemera — important, don’t get me wrong, but we all knew its place and form in our world.

Thirteen years later, I now know Facebook to be a shape-shifter. It appears to me one moment as a temptress, with ads for expensive dresses I’ve clicked on elsewhere (lifelong habit, I guess). The next it’s a sober scholar, lecturing me on the news. It remains a photo album, digitally pasted with old friends, dead relatives and past lives, but it’s shed that earnest, embryonic form of itself. My data, memories and digital habits fuel its everyday metamorphosis — there’s something unsettling in that. Maybe Facebook was never earnest, even in its most nascent form.

The advantages of that shape-shifting were plain to see while watching Mark Zuckerberg testify before Congress this week. The revelation that Cambridge Analytica mined 87 million Facebook users’ data without their knowledge seemed to drive lawmakers to the realization that governmental regulation of Facebook might be a necessity. At the heart of every question of regulation is a single idea: how to balance the rights of the individual with corporate and political interests. And the areas in which the government might regulate Facebook are numerous: privacy protection, monopolistic practices, political ads, free speech and racial discrimination, etc. But how do you regulate something that’s so hard to pin down?

Facebook can slip in and out of guises, wearing whichever one suits its purpose. “Is Facebook a media company?” Rep. Greg Walden asked. No, it’s a tech company, was Zuckerberg’s answer. But do purely tech companies find the need to engage legions of fact-checkers or nab the broadcast rights to 25 MLB games?

Some members of Congress have rightly been taken to task for not understanding the nuances of Facebook and failing to ask incisive follow-up questions. But even the ones who did know what they were talking about were largely ineffective in their sparring with Zuckerberg because they did so on multiple fronts. There were so many threads of questioning that they never quite knit together into a net. And so Zuckerberg, with his close-cropped schoolboy cut and new suit, slipped through Congress’s grasp.

Sens. Lindsey Graham and Dan Sullivan wanted to know if Facebook might have a monopoly on a particular method of communication that might stifle innovation and limit consumer choice. “When companies become big and powerful and accumulate a lot of wealth and power, what typically happens from this body is an instinct to either regulate or break up,” Sullivan said. Sen. Amy Klobuchar brought up legislation to regulate political ads on Facebook, something Zuckerberg has already announced his support for. Sen. Cory Booker and others brought up revelations from ProPublica that Facebook still allowed housing advertisements to target specific racial groups, bringing it in violation of Fair Housing Act provisions. Some, like Sen. Ben Sasse, tackled how Facebook might be stifling expressions of free speech.

But it was Congress’s concern about privacy issues that dominated regulation talk, perhaps natural given the ostensible reason for the hearings. Sen. Dick Durbin pressed Zuckerberg, saying, “I think that may be what this is all about. Your right to privacy. The limits of your right to privacy. And how much you give away in modern America, in the name of, quote, connecting people around the world.” Likewise, Sen. Maria Cantwell dug into Zuckerberg over a consent decree Facebook entered into with the Federal Trade Commission in 2011. The Washington Post wrote that the decree language “was written to require Facebook to identify and address emerging threats to user privacy as its business practices changed over the 20-year term of the consent decree.” Cantwell expressed skepticism that Zuckerberg and his company were adhering to the terms of that agreement. “When … I look at where you are from the 2011 consent decree and where you are today, I’m thinking, ‘Is this guy outfoxing the foxes, or is he going along with what is a major trend in an information age: to try to harvest information for political forces?’”

Throughout it all, Zuckerberg held on to the obtuse talking point that Facebook doesn’t own users’ data — users do. The company doesn’t sell data, was Zuckerberg’s constant refrain. The senators and representatives, though, seemed to see through that. “You clearly rent it,” Sen. John Cornyn said. “We might own our own data,” Rep. Doris Matsui pointed out, but “once it’s used in advertising, we lose control of it.”

Cornyn and Matsui’s points and Zuckerberg’s stonewalling get to the heart of the problem with Facebook: Shape-shifter that it is, it’s in the company’s interest not to acknowledge how fluidly it switches between personal data merchant, media monolith and tech platform. Congress’s categorization of Facebook has yet to happen: Tech company? Media company? Monopolistic enterprise? That categorization duty, and the attending responsibilities of regulation, will fall, in the coming months and years, to our nation’s politicians. Given this week’s hearings, that thought is far from comforting.