Former Rep. Beto O'Rourke, a hot Democratic prospect for 2020, posted a video of a dental cleaning to his Instagram story yesterday, a make-it-stop moment that showed how different 2020 will be online.

• Elizabeth Warren joked during an Instagram live video, filmed in her kitchen on New Year’s Eve, that she drinks "Michelob Ultra — the club soda of beers."

Instagram is the new fad for politicians trying to communicate with younger voters in an authentic way — but the more they use it, the lamer the content is going to get, Axios' Alexi McCammond writes.

• Just being on the platform doesn't automatically give veteran politicians the same swag as Beto or AOC (Rep. Alexandria Ocasio-Cortez, whose "Instagram feed is a master class in political brand building," per WIRED).

O'Rourke (age 46) and Ocasio-Cortez (29), who combined have over 2 million Instagram followers, made live-streaming a staples of their 2018 campaigns.

• Appearing as an "unfiltered" version of yourself on social media is natural for a 29-year-old. It's not so natural for those who look like they could be your parents.
• Hillary Clinton learned that the hard way in 2015 when she used Snapchat to tell her followers that she was "just chillin' in Cedar Rapids." She instantly became a meme.

How they use it: Ocasio-Cortez makes mac and cheese while talking about her progressive platform or addressing her critics.

• O'Rourke goes to Whataburger or plays the air drums in his minivan while discussing politics.
• People are drawn to their quotidian content because they've already bought into their personalities.

Everyone's experimenting:

• Ohio Sen. Sherrod Brown, who's 66 and has almost 10,000 Instagram followers, has used the platform to talk directly to voters. Sen. Cory Booker, 49, tweeted last year that Brown has a "VERY good Instagram."
• Sen. Kirsten Gillibrand (52), who has posted recipes before, baked a berry cobbler on New Year's Eve on Instagram.
• A Reddit user wrote: "It’s worth it if we get to see Bernie fussily making goulash while yelling about the Post Office."

The bottom line: Just because it's live doesn't mean it's raw. Or good.

Another ominous clue that the shutdown could be prolonged: President Trump tweeted yesterday: "I am respectfully cancelling my very important trip to Davos." He had been scheduled to leave Jan. 21 — 10 days from now.

• The shutdown sets a new record today, matching the longest stoppage yet: a 21-day closure that ended Jan. 6, 1996, under President Bill Clinton.
• Tomorrow sets a new record for longest shutdown.
• 800,000 federal workers won't receive paychecks due today. (AP)

Shutdown fallout:

• "White House officials [are considering] diverting emergency aid from storm- and fire-ravaged Puerto Rico, Florida, Texas and California to build a border barrier, perhaps under an emergency declaration," per the N.Y. Times.
• Cleanups at Superfund sites are suspended around the nation, "deepening the mistrust and resentment of surrounding residents who feel people in power long ago abandoned them." (AP)
• "With more federal security screeners refusing to work without pay, Miami International Airport plans to cut off access to one of its terminals over the weekend ... to send TSA workers to busier checkpoints." (Miami Herald)

What's closed, per AP: "Nine of the 15 Cabinet-level departments have not been funded, including Agriculture, Homeland Security, State, Transportation, Interior and Justice. Some iconic National Park facilities are shuttered as are the Smithsonian museums and the National Zoo in Washington. Nearly everyone at NASA is being told to stay home, as are most at the Internal Revenue Service, ... though the administration says tax refunds will be issued during the shutdown."

• Who's working but not getting paid: "Some 420,000 federal employees ... are working without pay, including the FBI, TSA and other federal law enforcement officers. Some staff at the State and Homeland Security departments are also working without compensation. The Senate has approved a bill to provide back pay to federal workers. The House must vote on it. Trump said this week that federal workers will 'get their money.'"

A reporter asks President Trump on the South Lawn, as he headed to Marine One for the border trip: "Does the buck stop with you over this shutdown?"

• The President: "The buck stops with everybody."

Many Republicans tuned out the Democratic response to President Trump's Oval Office address while Democrats tended to watch both speeches, according to a SurveyMonkey poll.

• Trump's speech drew an estimated 43.3 million viewers (compared with 25 million for the college football championship). The initial estimate from Nielsen had omitted CBS viewership. (AP)

"The Mueller team's questioning ... shows their interest in obstruction extends beyond the President's firing of FBI Director James Comey," CNN's Evan Perez, Pamela Brown and Laura Jarrett report:

• "One witness who worked closely with Trump [said] that, based on the questions asked, it is clear Mueller is looking at the President's "changing stories" as a way to possibly show corrupt intent in the obstruction probe."
• "Prosecutors appear to be examining the President's public statements ... to determine whether there's an effort to try to influence other witnesses and cause other administration and former campaign officials to make false public statements."

Talking about "big tech" is making less sense: The giants increasingly are trying to differentiate their business models, and Washington realizes they can't be lumped together, Axios' David McCabe and Scott Rosenberg write.

• Industry insiders have always known their differences are as pronounced as their shared traits. Now investors are catching on.
• Investors fell in love with a basket of stocks known as FAANG (Facebook, Apple, Amazon, Netflix and Google) and rode those investments up a tall curve for years.
• But last year's volatile market put an end to the group's collective ascent.

Policymakers and regulators found it convenient to paint a single big target on "the big tech platforms" amid privacy and election controversies.

• But the closer the government looks at the companies' problems, the harder it gets to settle on any one-size-fits-all solution.

Now watch the companies go their separate ways: This week, Apple greeted Las Vegas' Consumer Electronics Show multitudes with a billboard that read, "What happens on your iPhone stays on your iPhone."

• The message — "We won't exploit your data like our competitors" — highlighted the fault line between companies that depend on ads, like Google and Facebook, and those that sell products, like Apple. (Amazon sells both.)

"Trade wars, China’s slowdown, erratic stock markets: The outlook is getting grimmer for an increasing number of companies across the globe," Bloomberg's Cecile Daurat writes:

• Just yesterday, "more than a half-dozen corporate giants either lowered their profit forecast, announced massive job cuts or pulled plans in the face of market volatility."
• "American Airlines Group Inc., Jaguar Land Rover, Macy’s Inc. and BlackRock Inc. were among the biggest casualties, joining the likes of Apple Inc. and FedEx Corp. that have warned recently that the future isn’t looking as good as it did just a few weeks ago."

China "is more than ever consumed by the pursuit of national greatness," The Economist writes in its lead editorial:

• "China’s landing of a spacecraft on the far side of the Moon on January 3rd, a first for any country, was a mark of its soaring ambition."
• "President Xi Jinping is counting on being able to harness leading-edge research even as the Communist Party tightens its stranglehold on politics."
• We should be doing this: "Xi talks of science and technology as a national project."

Why it matters: "Amid the growing rivalry between China and America, many in the West fear that he will succeed."

This full-page ad appears today in The Washington Post.

Columbia president and CEO Tim Boyle, who has been with the company since 1971, told me in an exclusive interview from HQ in Portland, Ore.:

• "We rely on the beauty of America, the West, the outdoors to market our products. ... When that’s under stress, we feel like we have to challenge that.”
• "This is a time when the country is incredibly vulnerable. If you were an enemy of the United States, this is a time you’d want to attack us."
• "No party hates the outdoors except maybe the Donner Party."

"Baby shark! (Doo Doo Doo Doo Doo Doo) ... Billboard chart! (Doo Doo Doo Doo Doo Doo)" — N.Y. Times' Daniel Victor:

• The infectious song "Baby Shark" has "entered the Billboard Hot 100 chart at No. 32, ... placing Pinkfong, a South Korean educational brand, alongside the world’s top musical artists."
• "Baby Shark" has been viewed "more than 2.1 billion times on YouTube, making it among the 30 most-viewed videos ever."
• Pinkfong USA said that the digital content company is "creating toys, DVDs and other consumer products, including books and diapers."

Be smart, from NPR's Joshua Bote: "Much of the song's popularity, of course, just has to do with the fickle nature of the Internet, which [magnifies] the strange and the novel and continues to be hard to focus-group."

• Watch on YouTube.