WHEN WHATSAPP CAME DOWN

That was a painful 13 hours.

Brazil woke up in a weird sort of time travel – all the way back to 2012 – on Thursday after a judge ordered a 48-hour shut down of the messaging app WhatsApp, beginning at midnight local time.

WhatsApp, which is owned by Facebook, is the second-most-used app in Brazil, after its parent company's. More than 100 million people here use it, or 91 per cent of Brazilians on mobile, according to the Institute of Technology and Society in Rio.

"For Canadians, imagine that you cannot have access to anyone on the Internet – this is the impact it has on this country," said Fabro Steibel, director of the institute.

To the relief of millions, an appeals court judge overturned the ruling just before 1 p.m., invoking "constitutional principles" and saying "it does not seem reasonable that millions of users are affected because of the inertia of a company."

WhatsApp is a primary communications channel for schools, doctors, families, Congress members and drug dealers. Earlier this year a local politician was arrested after ditching out of her small town and running the place via WhatsApp from the mall in the city.

The shutdown order was issued by a judge in an industrial city in Sao Paulo state, in an attempt to force the company to provide user data as part of a criminal trial. The case is sealed and the court would not provide further information, but Brazilian media say prosecutors are seeking access to messages exchanged on WhatsApp by the accused.

The judge who overturned the ban said it should be possible to force WhatsApp to comply without cutting people off, and suggested a massive fine instead.

Mr. Steibel said the ban was beyond comprehension, within Brazil or beyond its borders. "It's very hard to understand, how you could have one court make a ruling that affects the whole country on this scale," he added, saying it "says a great deal about technology and society in Brazil in 2015," and how institutions have been slow to catch up with how people really live.

The country's telecom carriers scrambled to enforce the ban; only one, Oi, went to court to try to stop it. There is no love lost between WhatsApp and the big telcos, who see it as an Uber-like intruder that doesn't play by the rules, not paying the same taxes or fees they do. In recent months, telecom firms have been heavily lobbying Congress to regulate the app.

WhatsApp shaved the amount of time Brazilians spent calling people on their phones to 111 minutes a month from 132 minutes between 2014 and 2015, according to research by Teleco, a consulting firm.

Mark Zuckerberg, the CEO of Facebook, seemed startled to discover that a single judge could shut down the messaging juggernaut.

"I am stunned that our efforts to protect people's data would result in such an extreme decision by a single judge to punish every person in Brazil who uses WhatsApp," he said in a post on, of course, Facebook. "This is a sad day for Brazil. Until today, Brazil has been an ally in creating an open Internet."

Many Brazilians took to social media to also call the decision retrograde, decrying a system where one official in an obscure city was able to disrupt the lives of millions of people. "This country is like Cuba," complained one woman on Twitter.

The WhatsApp ban was possible due to a feature of the Brazilian legal system, which means one local court judge's ruling applies to the country as a whole and even a telecom giant must comply or face sanction. WhatsApp, in refusing to respond to the judge's request for data, has apparently been taking the line that because its offices are in California and it has no Brazilian corporate presence, it is not bound by the court's orders. (The company has not responded to questions about this ban.)

The bare-bones app facilitates the easy exchange of text and voice messages, pictures and video. It consumes minimal data, which makes it extremely popular with Brazilians, who face some of the highest mobile package tariffs in the world. It also offers a calling service that works on a data plan, making it far cheaper than carrier-based voice calls. Low-income Brazilians use – or used – it for almost all of their communications.

Amos Genish, the president of Vivo, the largest cellphone carrier in the market, called WhatsApp "piracy" and "a provider without a licence" in October. "They use our [telephone] numbers to send free messages," he complained, noting that Vivo pays a fee per active number.

The shutdown immediately spawned, of course, a hashtag in social-media-crazy Brazil: #Nessas48HorasEuVou, or, "In these 48 hours I will …" One Twitter user said she planned to "find out who these people who live in my house are," while others said they would "die," "catch up on sleep" and "be alone, of course."

Some offered pictures of themselves subsituting WhatsApp with handwritten letters or messages picked out on ancient typewriters.

WhatsApp's creator, Jan Koum, said on Twitter that the company is "disappointed in the short-sighted decision to cut off access to WhatsApp, a communication tool that so many Brazilians have come to depend on, and sad to see Brazil isolate itself from the rest of the world."

The immediate beneficiary of the shutdown, meanwhile, was the rival app Telegram, which saw more than 1.5 million new users sign up in five hours. The company began to post pleading tweets, saying they had "all hands on deck to accommodate the crazy load" and for new Brazilian users to be patient while they waited for sign-up codes via text message. The company seemed to be caught so off-guard that it had no capacity to post any of the messages in Portuguese.

Telegram was founded by Russian brothers and is based in Germany. It rivals WhatsApp in other emerging-market countries but until now had struggled to crack Brazil.

Facebook bought WhatsApp in 2014 for $2-billion (U.S.); it was little known in North America then but widely used in Latin America and South Asia. WhatsApp has no ads, and users do not pay a per-message fee as they do with an SMS. It's a free download for the first year and $1 a year after that.

ALSO ON THE GLOBE AND MAIL

WhatsApp in Brazil: More reading