In the brief, heady period at the start of the uprising in the Libyan capital against Muammar Gaddafi, activists relied on Facebook and text messages to network, organise and express themselves.
But then the government shut down the Internet and SMS text messaging from mobile phones, effectively throwing the anti-Gaddafi movement into the dark.
The Libyan authorities may have learned a lesson from neighbouring Tunisia and Egypt, where opposition activists this year used Facebook and Twitter to organise themselves in January and force out those two countries' autocratic leaders.
"I was on Facebook all the time in the early days of the uprising," said an activist from the February 17 Young Women's Coalition who used the name Amal.
Along with three other activists, she met Reuters reporters in central Tripoli this week. Fearing arrest, they asked that their identities, and the location of the meeting, be withheld.
"The government monitors phone calls, so no Internet and no texting makes it difficult for us to communicate," Amal said.
"Basically every information we communicate with each other has to be by word of mouth or we have to talk in code over the telephone," she added.
BACK IN TIME
Opponents of Gaddafi in the Libyan capital say they have had to revert to the kind of methods of communication used by dissidents and revolutionaries before the age of social media.
Unable to build networks on Facebook and Twitter, they have had to feel their way around slowly, the "old-fashioned way", to make contact with like-minded people in other neighbourhoods.
"It is difficult to reach other groups," said an activist who gave his name as Salim.
"There is a lot of fear and people don't trust each other."
The U.S. government and its allies are promoting "shadow" Internet and cellphone systems across the world to help opponents of hostile, authoritarian governments, a U.S. newspaper said this month. If so, there is little evidence that any of this help has yet reached Tripoli's activists.
Apart from having to be careful of what they say over the phone because of government eavesdropping, Libyans who describe themselves as part of anti-Gaddafi networks say they also have to watch out for the government's web of informants. Activists here say they run the risk of arrest, torture and death.
"The single most powerful tool the regime has is informants.
That's the tool we fear the most," said an activist who uses the name Niz, one of the few in Tripoli who manages to maintain contact with the outside world on a secure Internet service.
Officials in Gaddafi's administration deny suppressing dissent.
They say the vast majority of people in Tripoli back the Libyan leader, and that the few who do not are criminals and al Qaeda militants.
Doing anything under the gaze of Gaddafi's security apparatus takes time, Niz said.
To avoid detection, four activists who met Reuters reporters in the capital this week had to hold a series of meetings with each other in person to set it up.
"It's all a question of trust," said one of the group, who gave her name as Fatima. "You have to meet someone face to face in order to make a connection."
Niz said that he was in direct contact with four other groups in Tripoli, three of them in neighbourhoods known for their opposition to the regime, and knows the names of five others. Too much information could be bad for him, and them.
Other groups prefer to remain under the radar entirely from each other and do their own thing. Some groups are peaceful, others attack government checkpoints at night, he said.
Niz said his group had just around 20 members at the moment but was working to expand through the same laborious, face-to-face methods. "It's a crude way of expanding and everything takes longer," Niz said. "But we are growing."
Activists say the Gaddafi regime has tightened security in Tripoli, making opposition to the government difficult.
Niz's Free Generation Movement focuses on symbolic acts for now, he said -- painting a rebel flag on a road, unfurling flags from bridges or even sending a rebel flag flying over the city hanging from Chinese lanterns.
Despite the great risks, all their acts are filmed with basic cameras, and the footage circulated. These are acts that are dangerous "but which let people know there is an active opposition here", said Niz.
The Free Generation Movement has also been effective in reaching out to international media organisations, updating them on news as well as uploading to the Internet amateur videos of anti-Gaddafi demonstrations in the city.
Another group in Tripoli, which he did not name, was putting together a "centralised, comprehensive list of informers," neighbourhood by neighbourhood, said Niz.
Again, this is a slow process, but one that the activists Reuters spoke to said is gradually gaining momentum.
"The regime has done things to slow us down," Niz said. "But banning the internet will not stop us. Stopping SMS will not stop us."
"They can delay us but they cannot stop the inevitable collapse of the regime."