It is turnover season in tech, and I’m trying to figure out why.

The Instagram founders called it quits last week. They’re seriously rich and young enough to do something else. Or many somethings else.

Also last week Oracle disclosed without explanation the departure of Thomas Kurian, the company’s president for products and the man considered Larry Ellison’s technical deputy. (Kurian figured prominently in my contentious 2015 profile of Oracle co-CEO Mark Hurd; I quoted an anonymous Oracle leader calling Kurian “a giant pulsing brain that is most like Larry.”) Kurian worked at Oracle for decades and also has time for another career.

Then there’s Sridar Ramaswamy, Google’s top executive for its ads business, which is most of its business. Google said Monday he’ll join Greylock, a venture capital firm, as a venture partner. That’s a term of art in an industry where terms of art matter that means he’ll make investments but isn’t yet a full-on member of the team. (The inimitable Fred Wilson, a founding and full-on partner at Union Square Ventures, explains the nuances of venture partnerdom here.)

Is there a rhyme or reason for all these middle aged men, all long tenured in their jobs, leaving now? Investment bankers tend to leave in February or so, minutes after their annual bonuses show up in their checking accounts. But tech execs follow less of a scripted calendar.

Maybe they spent their summers either enjoying themselves, or, for the umpteenth time, watched their families enjoying themselves, and decided enough was enough.

One thing is nearly certain: There will be no neighborhood bake sales to make sure these gentlemen are well provided for in their dotage.

NEWSWORTHY

No one is irreplaceable. As Adam mentioned, Instagram's co-founders are leaving. Facebook on Monday said longtime executive Adam Mosseri, who had been vice president of product, would take over the unit. Mosseri's first task may be to replace all the talent that's left recently, including heads of engineering, operations, and (his own prior job) product. At Google, Prabhakar Raghavan, vice president of cloud apps, will replace departing advertising head Sridhar Ramaswamy. And at Oracle, Business Insider semi-speculates/reports that recently recruited former Microsoft exec T.K. Anand may take over for Kurian.

No one knows everything. Speaking at at Fortune’s Most Powerful Women Summit, Google and Alphabet CFO Ruth Porat said she had learned a lesson about privacy after the recent controversies. “The key lesson is, we need to constantly raise the bar on ourselves,” she said. Catch some additional stories from the conference in the links below.

No one is immune. Microsoft co-founder Paul Allen says he has been struck by cancer for the third time, now a recurrence of the non-Hodgkin’s lymphoma that was first diagnosed in 2009. Allen owns the NBA’s Portland Trailblazers and the NFL’s Seattle Seahawks and recently gave $30 million towards a housing project in Seattle for homeless and low-income families.

Return to sender. Subscription Personalized online retailer Stitch Fix, which went public almost a year ago, disappointed Wall Street with its fiscal fourth quarter earnings. Revenue increased 23% to $318 million but the company forecast revenue for next quarter could grow as little as 20%, less than analysts expected. Shares of Stitch Fix, which had gained 73% this year, lost 22% in premarket trading on Tuesday. Investors were said to be wary of rising competition from Amazon. The e-commerce giant said it would raise the minimum wage it pays to $15 an hour. Including temps, part timers, and seasonal workers the decision covers all 350,000 employees. "We listened to our critics, thought hard about what we wanted to do, and decided we want to lead,” Jeff Bezos said.

Slow arrival. Verizon launched the first major 5G wireless service, offering home Internet service to consumers in parts of Houston, Los Angeles, Sacramento, and Indianapolis. The carrier says it won't be offering mobile 5G service until next year, when 5G compatible phones start reaching the market.

Just desserts. Venture capital billionaire Vinod Khosla was rebuffed by the Supreme Court in his decade long effort to keep people off a beach near his property in Half Moon Bay, Calif. The high court declined to hear an appeal of a lower court ruling that access to beaches is grandfathered even on private property.

Living bibliography. The amazing collection of human knowledge represented by Wikipedia has one major failing. The linked web pages used as citations often go offline after a few years. So the good folks at the Internet Archive have been trying to replace dead links at Wikipedia with the corresponding archived sites from their servers. On Monday, the archive announced it had fixed more than 9 million broken Wikipedia links. More than 25,000 clicks a day from Wikipedia readers now go links from the Archive's Wayback Machine.

FOOD FOR THOUGHT

Reporters and human rights activists in some countries are literally risking their lives to get information out about abuses. Some have discovered an insidious high-tech way that repressive countries can try to track and thwart their efforts. It's an app known as Pegasus that can turn a smartphone into an advanced tracking and listening device. Avi Asher-Schapiro has an in-depth report on Pegasus for the Columbia Journalism Review, and it's not an easy story to read.

Citizen Lab has been tracking Pegasus—which the NSO Group says is intended for legitimate anti-terror and law enforcement activities—for years. It was first detected on the phone of Ahmed Mansour, a human rights activist in the United Arab Emirates, in 2016. “It was more sophisticated than anything I’d ever seen before,” Bill Marczak, the Citizen Lab researcher who first identified Pegasus on Mansour’s phone told me recently. Researchers knew about spyware that could siphon off some private data from cell phones, but Pegasus took things further: It could completely take over a phone remotely, without the owner knowing, and without leaving any trace besides a text message.

IN CASE YOU MISSED IT

MPW: Why We Should Stop Worrying About A.I. (And Start Worrying About Data) By Kristen Bellstrom

MPW: OpenTable CEO Christa Quarles: To Check Diversity Progress, Look at Who You Hired Last Quarter By Emma Hinchliffe

MPW: Want to Innovate with Purpose? Don't Ask for Permission. By Andrew Nusca

Here Comes the Third Wave of Cord Cutting: Home Internet Service By Aaron Pressman

Google Maps Update Aims at Improving Your Daily Commute By Don Reisinger

Amazon's 'Free Dive' Ad-Supported TV Streaming Service to Launch as Early as This Week, Report Says By Kevin Kelleher

Netflix Might Let Viewers Decide Storylines By Don Reisinger

BEFORE YOU GO

Ever heard of optical tweezers or microscopic drilling? Well, these two techniques for manipulating tiny objects via lasers that are used to clear blocked arteries and perform corrective eye surgery, respectively, just won the Nobel Prize in physics. Arthur Ashkin invented the optical tweezer and Gérard Mourou and Donna Strickland get the award for their laser pulse drilling method. Strickland's win is the first time in 55 years that a woman has won the Nobel for physics.

This edition of Data Sheet was curated by Aaron Pressman. Find past issues, and sign up for other Fortune newsletters.