The word spread through the encrypted app Telegram, and later, Twitter. On the agreed-upon day, the Cuban people would unite with one voice.

Not to clamour for democracy, or turn out the government, or demand the freedom of political prisoners.

To protest high mobile internet prices.

The overwhelming response - thousands of tweets under the hashtag #BajenLosPreciosDeInternet - became by some estimates the largest protest, albeit digital, to wash over the communist island in years. Dissidents long monitored by the government joined the cause. But so, too, did students, private-sector business owners and other Cubans who appeared to be anything but counterrevolutionaries.

They weren't demanding political change. They were saying they wanted their government to be more responsive.

Cuba: Wifi means family Show all 13 1 /13 Cuba: Wifi means family Cuba: Wifi means family Doctor Alejandro Soto stands with his dog Coco as he connects to an internet hotspot in Havana Reuters Cuba: Wifi means family Gathering at a hotspot in Regla Reuters Cuba: Wifi means family A dancer uses a hotspot from inside a bus before performing at the Carnival of Havana Reuters Cuba: Wifi means family A woman sits on a vintage car as she uses a hotspot in Havana Reuters Cuba: Wifi means family A hotspot connection at the sea front at the Malecon in Havana Reuters Cuba: Wifi means family A hotspot in Havana Reuters Cuba: Wifi means family Dancers use a hotspot before performing at the Carnival of Havana Reuters Cuba: Wifi means family Tourist guide Daniel Hernandez, 26, sits on his Russian-made car as he speaks to his girlfriend who lives in Britain Reuters Cuba: Wifi means family People connecting to the internet at a hotspot in Regla Reuters Cuba: Wifi means family Claudia Espinosa (right) and her mother Maribel Sosa speak to relatives living in the United States at an internet hotspot in Havana Reuters Cuba: Wifi means family An internet hotspot at the sea front at the Malecon in Havana Reuters Cuba: Wifi means family A hotspot in Havana REUTERS Cuba: Wifi means family People make a video-call inside a car at a hotspot in Havana Reuters

"Social networks are revolutionizing Cuba," a 20-year-old Havana salesman who helped launch the June protest said in a text interview via Telegram. "This is the only way they are going to hear us."

In a world forever altered by social media, Cuba was one of the last frontiers. Home access to the web began expanding in 2008, but it was still limited mostly to the government elite and vetted professionals. For most Cubans, tapping the internet meant travelling to a public hotspot, buying a scratch-off phone card and surfing on a cut-rate smartphone.

All that changed seven months ago, when this nation of more than 11 million took a great leap forward with the introduction of 3G mobile telephone service - an advance that permits those Cubans who can afford it to access the internet anywhere and anytime they have cellular coverage.

The cost, $7 a month for the cheapest package, remains out of reach for many in a country where the median monthly income is $44. Nevertheless, a surging number of Cubans - more than 2.2 million - are accessing 3G service. That's giving rise to a new class of netizens, who are organising behind causes and social movements in a manner not seen since the Cuban revolution.

For years, Cuban censors have blocked websites they've deemed politically sensitive. But the government has surprised some observers by not yet following the example of countries such as China, which blocks popular social media sites, including Facebook and Twitter.

President Miguel Diaz-Canel, who took over the nation's leadership from Raul Castro last year, and other top Cuban officials have embraced social media - opening new Twitter accounts, for example. In May, the government took steps to allow private home Wi-Fi more broadly.

In response, some Cubans are flexing their digital muscles, tweeting complaints and daily concerns directly to senior apparatchiks.

Some Cuban officials, unused to being held accountable by the people, have reacted by blocking complainers and branding others trolls. But others have proved far more responsive. After a university professor called out the government on Facebook for cutting trees in a neighbourhood park, the vice president of the local government replied directly with a highly detailed - and highly technical - explanation.

"Years ago, when we had Fidel, you could write him a respectful letter, telling him your roof needed repair or something," said Liber Puente, CEO of the Havana-based IT firm TostoneT. "And if you were lucky, repair teams would suddenly show up - sometimes with Fidel.

"Now, Cuban Twitter users are again going direct to their government - and some are not being nearly as polite as before," he said.

President Miguel Diaz-Canel (second L) has embraced social media since succeeding the Cuba's more traditional former leader Fidel Castro (AFP/Getty)

President Diaz-Canel's active presence on Twitter has earned him 136,000 followers since he joined in August. But his tweets have also attracted trolls. While some of his digital hecklers hail from the U.S.-based Cuban American community, others appear to be living in Cuba, unafraid to challenge the president publicly.

Recently, for instance, Mr Diaz-Canel tweeted praise for the new leadership of the University Students Federation, a student movement known by its initials in Spanish, FEU. It brought slams from users such as Jose Alberto, a self-described Christian living on the island, who blasted the president: "If the FEU honored its long history of struggle, the first thing it would do is combat you, phony."

Camilo Condis, general manager of Artecorte, a community project in Havana, is one of Cuba's new internet gadflies.

He has needled the education minister over misspellings on his Twitter account. In January, he and others took to social media to slam the problematic transit system. He routinely engages senior ministers online, with responses ranging from thoughtful replies to rebukes. After one series of critical tweets, Jorge Luis, Cuba's communications minister, blocked him.

"I think that the best path would be for the government to listen more to the people, and that they should be accountable," Mr Condis said. "Many things can be changed in Cuba without hurting the revolutionary process."

For some Cubans, the arrival of social media has proved cathartic. Since 2015, Isabel Cabello, a 60-year-old physician, has anguished over the death of her pregnant daughter in a Havana hospital. She has pressed her case against the medical staff to prosecutors and the health ministry, insisting they be prosecuted for negligence.

Frustrated by a lack of movement in the case, she joined Twitter in March. On Mother's Day, after Vice President Roberto Morales Ojeda tweeted a greeting to Cuban mothers, she called him inhuman and said he'd destroyed her life.

Mr Morales' reply: "Doctor, the loss of a daughter or son is not recoverable for the parents and relatives, and is painful to all. But you have received responses on many occasions of investigations into the death of your daughter. . . . Stop questioning."

Nevertheless, Ms Cabello said she has taken comfort in an outpouring of online support.

The relaxing of online censorship under president Diaz-Canel has brought Cubans onto the streets with a renewed confidence in expressing their views

"Things have completely changed," she said. "I feel supported now. . . . I know officials, including President Diaz-Canel, are seeing my messages, and that the world now knows the terrible thing that happened to my daughter. Nothing can be hidden now. No more lies or propaganda can hide my daughter's death."

In April, the Cuban government authorised an animal rights demonstration that drew hundreds to the streets of Havana. It had been promoted largely on social media.

Much of the online action is being conducted within certain parameters of debate. Cuba remains a one-party, authoritarian state, and users aren't challenging the revolution or its leaders; they're focusing on more local and more personal concerns. The approach amounts to a tactical acceptance of the island's communist system.

But there are signs that the criticism and complaints might be veering into terrain that's less comfortable for the government.

After the internet price protest, pro-government media blamed the campaign on U.S.-backed "mercenaries." Organisers and participants deny the charge.

"This has nothing to do with the United States or Cuban Americans," said the 20-year-old organiser, who spoke on the condition of anonymity out of concern for retaliation. "The people are tired of these same old lies."

LGBT activists arrested at unauthorised pride march in Cuba

In a move that some say indicates a growing unease with web-based people power, the Cuban authorities this spring abruptly banned a gay pride parade in the capital that had been organised largely online. Even the notice of cancellation came via social media: Cuba's National Centre for Sex Education said on Facebook that the event had been scrapped because of "new tensions in the international and regional context."

Organisers, undaunted, quickly regrouped on social media, and hundreds turned out in defiance of the ban. They marched about a half-mile before being stopped by police, who detained several participants.

"When they started detaining people, they were looking for a leader," said Norges Rodriguez, a 31-year-old activist for gay rights. "But since it was organised through social media, there was no specific leader."

Mr Rodriguez and his husband, Taylor Torres Escalona, 33, have helped introduce Cubans to the power of web-based social satire. After the government announced broad new food rationing in May, the couple tweeted a photo of themselves posing playfully in a long food line, under the hashtag #lacolachallenge - or #thelinechallenge.

The tragicomic tweet touched a nerve. A wave of Cubans posted their own selfies in food lines with the hashtag.



"I don't know if (government officials) realised exactly what they were doing" when they introduced 3G, Mr Rodriguez said. "But they can't take it back now."

Observers here say social media might also be providing a measure of security for journalists and activists.

One sunny morning in May, dissident journalist Luz Escobar sat in a dilapidated hotel by Havana's airport, interviewing residents displaced by a freak tornado that slammed into the capital last winter.

They were complaining to her of a poor government response, she said, "when the authorities suddenly came in."

Ms Escobar said she was hauled away by police, who told her she was not authorised to conduct such interviews. Her disappearance prompted a rapid response on Twitter: More than 1,000 users spread news of her detention.

Within five hours, she said, she was freed by authorities.

"My feeling is that (the Twitter campaign) had an impact," she said. "I was impressed by the solidarity on Twitter coming from people I didn't know. Some of them had nothing to do with the media. They were just citizens, artists, whoever."

"Social media," she said, "is amazing."