Recode Daily: Kicking the Facebook habit — even for a month — might make you healthier and happier

Cutting Facebook out of your life even temporarily turns out to have consequences — and many of them are positive. Last year, Stanford researchers asked thousands of Facebook users how much they would need to be paid to give up their account for a month. Among the key findings: People who gave up Facebook spent less time overall online; they were less informed, but also less politically polarized; there was positive impact on people’s health and well-being; and the study subjects said they planned to spend less time on Facebook in the future. “This isn’t the first study to explore the health effects of social networks. But in a world where Facebook is now used by more than 2.3 billion people per month, studying its impact on mental health, news distribution, and tech addition has never been more important.” [Kurt Wagner / Recode]

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Calling his former boss “a racist,” “a con man” and “a cheat,” Michael Cohen, the former lawyer and “fixer” for President Donald Trump, took the stand to testify publicly against Trump before the House Oversight Committee. Cohen, who built his career and identity by making Trump’s problems go away, alleged to Congress how Trump “manipulated financial records, paid to cover up extramarital affairs, and reacted with glee when he learned in advance that the WikiLeaks anti-secrecy organization would release emails damaging to his political opponent.” Cohen also dropped the revelation that federal prosecutors in Manhattan are investigating previously undisclosed wrongdoing related to the US president. Trump’s Republican allies aggressively questioned Cohen’s credibility and motives for speaking out. Here is Cohen’s prepared testimony; you can follow his statements with this time-stamped analysis from New York Times reporters. [Matt Zapotosky, Rosalind S. Helderman, Karoun Demirjian, and Rachael Blade / The Washington Post]

Meanwhile, more than 8,000 miles away in Hanoi, Vietnam, Trump publicly embraced North Korean leader Kim Jong Un as they opened a two-day nuclear summit. Trump referred to the brutal authoritarian dictator as “my friend,” and tweeted after a social dinner of grilled sirloin and chocolate lava cake that the two had “very good dialogue.” US negotiators are seeking “detailed commitments from Pyongyang to dismantle at least some of its nuclear weapons facilities, while Kim’s regime wants relief from punishing economic sanctions and a declaration to formally end the Korean War.” [David Nakamura and Simon Denyer / The Washington Post]

Jack Dorsey’s other company — the payment startup Square — reported fourth-quarter results that beat Wall Street’s expectations for earnings and revenue, though analysts were disappointed by Q1 projections. Despite solid growth — $464 million of adjusted revenue for Q4 (a year-over-year rise of 64 percent) and earnings per share of 14 cents (a 6-cent increase from a year earlier) — shares fell more than 7 percent in after-hours trading. Square’s peer-to-peer Cash App also showed positive growth, with more than 15 million monthly active customers in December 2018 — doubling from a year earlier. Dorsey said that more than half of Square’s adjusted revenue came from products Square created in the last five years, while attributing Cash App’s growth in downloads to a “network effect” of friends and families. [Kate Rooney / CNBC]

The social media app Musical.ly — which is now known as TikTok — has been fined a record $5.7 million by federal regulators for violating the Children’s Online Privacy Protection Act. The Chinese-owned app, which has been downloaded more than 200 million times, was illegally hoovering up data from children under age 13, including names, email addresses, pictures, and locations. The app lets users make and share short videos (like Vine but 15 seconds); it has 65 million registered users in the US, and at last count was the fourth- and 25th-most popular free app on Google and Apple devices, respectively. [Craig Timberg and Tony Romm / The Washington Post]

At the tech trade show formerly known as Mobile World Congress, most of the 100,000 attendees and 2,400 companies ignored the US-led campaign against China’s Huawei, and focused instead on gadgets: foldable smartphones, 5G tech, AR goggles — and robots, of course. Here’s a words-and-pictures overview of what stood out at MWC Barcelona. [Adam Satariano and Edu Bayer / The New York Times]

A Y Combinator program was once exclusive. Then it accidentally let 15,000 people in — and decided that works a lot better. This all gets at a big question: Does Silicon Valley only work if there is some exclusion, some selectivity, and some prestige? Or can it scale? [Theodore Schleifer]

Meet J2’s Vivek Shah, the CEO quietly presiding over a $4 billion media business. The CEO of J2 Global, a company that owns a portfolio of media and internet service companies that includes PCMag, Mashable, and Speedtest by Ookla, on the latest Recode Media. [Peter Kafka]

When the bully is the boss.

Bill Gates on how we’ll reinvent the future.

This article originally appeared on Recode.net.