Today, I share a tale of two stocks. First, there’s Tenable Network Security ($TENB), the third cybersecurity firm to go public this year. This Columbia, Md.-based company, whose software helps defend corporate networks from digital attacks, follows Zscaler’s terrific market debut in March and Carbon Black’s equally admirable coming out party in May. Like its predecessors, which popped upon their introductions, Tenable made a stunning entrée on its first day of trading: shares surged by nearly a third to just above $30 per share on Thursday. One couldn’t hope for a better reception.

Indeed, the cybersecurity market rally shows no signs of flagging. As Tenable CEO Amit Yoran told CNBC, “As long as cybersecurity remains one of the foundational issues of our time, we believe that there will continue to be tremendous appetite in the market for understanding what your risk and exposure looks like.” There’s something to Yoran’s conviction, even if he is simply talking his own book.

Now, the counterpoint: the collapse of Facebook’s market value just a day prior to Tenable’s IPO. The media titan issued a weak earnings report on Wednesday, revealing slowed user and revenue growth and warning of chilled expectations for the foreseeable future. Investors, spooked, fled, wiping well over $100 billion off the company’s market cap. The ensuing nosedive erased all of the stock’s gains year-to-date.

What with fake news, the Cambridge Analytica scandal, GDPR—you name it—it’s been a rough year for Zuckerberg & Co. To this columnist’s eye, Facebook’s travails and Tenable’s triumph serve to remind that cybersecurity, and its close cousin privacy, are gaining in the estimation of consumers. The trajectory of these two stocks—one soaring, the other spiraling—demonstrates how businesses cannot ignore data protection without repercussions any longer. Those who have moved fast and broken things must stoop now to pick smashed pieces off the floor.

These market trends are good news for cybersecurity firms gearing up for the next highly anticipated IPOs: CrowdStrike, Tanium, and Cylance, among them. Investors’ enthusiasm for data-protecting businesses seems to swell even as the wrath loosed on companies that foul up amplifies. Mark the markets’ invisible hand, for it gestures.

Have a great weekend.

Robert Hackett

@rhhackett

robert.hackett@fortune.com

Welcome to the Cyber Saturday edition of Data Sheet, Fortune’sdaily tech newsletter. Fortune reporter Robert Hackett here. You may reach Robert Hackett via Twitter, Cryptocat, Jabber (see OTR fingerprint on my about.me), PGP encrypted email (see public key on my Keybase.io), Wickr, Signal, or however you (securely) prefer. Feedback welcome.

THREATS

Facebook crashes. Facebook shares lost nearly 25% of their value, wiping $120 billion off its market cap, after the company reported slowed user growth and weaker-than-expected revenue projections. The market plunge followed a host of privacy issues affecting the company—most notably, the blowback from Cambridge Analytica's alleged misuse of people's data and the enactment of GDPR, a new regulatory regime, in Europe. Meanwhile, BuzzFeed got a hold of a March memo penned by Facebook's outgoing security chief, Alex Stamos. In it, Stamos lays out what he believes Facebook must do to fix its problems, such as reeling in "creepy" data collection practices.

Google gets serious. Google had a number of security updates this week. The search giant said it will start selling hardware security keys, branded "titan," to corporate customers in an effort to combat phishing attacks and and hacking attempts. (Google uses such fobs to protect its own systems.) Google's cloud business said it is adding a feature to help G Suite administrators identify virus-infected computers and malware-laden files. Also, Google's Chrome browser has started labelling sites that don't encrypt Internet traffic with "HTTPS" as "Not Secure."

Life-unlocked. The website for Lifelock, an identity theft protection service now owned by cybersecurity giant Symantec, had a bug that exposed subscribers' email addresses. After journalist Brian Krebs contacted Symantec about the issue, the company took the site offline. The member portal is back up, and Symantec says the issue has been addressed.

V for Vendetta. Online disputes can lead to grudges, which can can lead to bizarre, horrible consequences. This piece by Kashmir Hill at Gizmodo tells the story of how an argument about the decorum one should exhibit on the site of a former concentration camp spiraled into a life-wrecking nightmare. The Internet is a weird place—be careful out there.

Hey, literal jailbreaking!

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ACCESS GRANTED

We tend to think of espionage in the United States as an East Coast phenomenon: shadowy foreign spies working out of embassies in Washington, or at missions to the United Nations in New York; dead drops in suburban Virginia woodlands, and surreptitious meetings on park benches in Manhattan’s gray dusk.

But foreign spies have been showing up uninvited, to San Francisco and Silicon Valley for a very long time. According to former U.S. intelligence officials, that’s true today more than ever. In fact, they warn—especially because of increasing Russian and Chinese aggressiveness, and the local concentration of world-leading science and technology firms—there’s a full-on epidemic of espionage on the West Coast right now. And even more worrisome, many of its targets are unprepared to deal with the growing threat.

FORTUNE RECON

Venmo’s Privacy Settings Could Be Exposing Your Biggest Secrets by David Z. Morris

Cylance Tech Chief Leaves to Helm Cyber Startup
by Robert Hackett

What Six Politicians Said About the Threat of Russia Hacking the U.S. Midterm Elections by McKenna Moore

GOP Senator: Trump Acting Like Dictator Over Security Clearances by Glenn Fleishman

Russian Hackers Could Have Caused 'Mass Blackouts,' Officials Say by Emily Price

Twitter's Plan to Clean Itself Up Involves Getting Rid of 143,000 Bad Apps by Jonathan Vanian

Google Cloud Grows With Target, Security, and Grammar Checker by Jonathan Vanian

The TSA and American Airlines Have a Plan to Make Airport Security Screenings Slightly Less Painful by Grace Dobush

ONE MORE THING

"I'm sorry, Dave. I'm afraid I can't do that." Andy Weir, author of The Martian, recently penned a short science fiction story called "Digitocracy." The premise: A human malcontent sets out to destroy an artificial intelligent computer system that runs the city of Wichita. It's a quick read—darkly funny—mostly dialogue. I like the Huxleyan way it blurs the line between utopia and dystopia.