As she makes her way past the art deco houses of Havana’s Miramar neighbourhood, there is little to suggest that Teresita Rodríguez is different from any other Cuban, running an errand or buying her groceries. But she is in fact a semi-legal data mule in the country’s “offline internet”.

Every morning, Rodriguez ferries external hard drives back and forth across Havana, using her feet to carry out the role that cables and wi-fi perform in other countries with less-restricted access to the world wide web.

Her job is both high-tech and extraordinarily simple. At one end, she sits and waits for a couple hours in the front room of the home of an information peddler, while he copies the latest terabyte-sized package of global films, TV dramas, comedies, magazines, applications and anti-virus software to her hard drive via a USB cable. She then takes those digital files to the home of her employer so he can download it and sell it on to his customers, many of whom will in turn charge their friends and neighbours for a copy.

These copies are known as the “Paquete Semanal” (Weekly Packet), a fast-spreading service that is enabling huge numbers of Cubans without internet access to obtain information just days – and sometimes hours – after it has gone online elsewhere in the world.

It is part of an alternative IT revolution in Cuba, where data-sharing has evolved in a very different way from elsewhere in the world as a result of government censorship, the US embargo and the creativity of an extremely well-educated and information-hungry population.

That environment looks set to change. When Barack Obama and Raúl Castro announced a resumption of diplomatic relations last week, their governments also promised an upgrade of the island’s communications infrastructure by US firms, who are being allowed to operate in Cuba for the first time in more than half a century.

It will have a major impact. Cuba has one of the lowest internet penetration rates in the world, with less than 5% of the island’s 11 million people connected according to the White House. Only a privileged few have access to private internet connections.

Most of those that do have access have to rely on dial-up connections, prompting Google chief Eric Schmidt to say during a trip to Havana earlier this year that the island was “trapped in the 1990s”. Faster lines are available at international hotels and “internet rooms”, but at a minimum charge of $5 an hour – a weekly wage for many people – it is beyond the financial means of the vast majority of the population.

The high cost and low speed are the result of a poor infrastructure and the government’s less-than-enthusiastic attitude toward the spread of information. The island’s only fibre-optic cable was connected by Venezuela several years ago, but it has limited capacity and the benefits haven’t spread widely due to poor telecom networks on the island.

Yet it would be wrong to assume that the island’s population have been living in an information black hole.

Thanks to the Weekly Packet, Cubans will this week be watching the final Hobbit movie as well as the most recent episodes of Homeland, Blacklist and Two and a Half Men; BBC documentaries; Japanese manga; Brazilian telenovelas and Korean melodramas. In addition, they can read the last editions of 500 magazines, including National Geographic, PC Weekly and the Economist, and play updated versions of Angry Birds and Fruit Ninja.

The terabyte-per-week service is cheaper than most internet providers. Prices range from $17 for the latest Friday upload (which is mostly paid by those who want to resell to their own customers) to $2.50 for copies made between Tuesday and Thursday, when the content is already a few days old and thus has little resale value.

“We get between 10 and 20 customers a day,” said Jorge Fernandez, who recently switched businesses from unlocking mobile phones to providing Weekly Packets. “The most popular shows are Vampire Diaries, Walking Dead, Breaking Bad and The 100.”

Like everyone in this article, he asked for his name to be changed because of the ambiguous legal status of his business: Fernandez has a permit only to burn CDs and is reluctant to say who is the original source of the latest terabytes of content. “It’s someone with high-speed internet. I don’t really know. I don’t ask,” he said.

Customers appear satisfied. “You can get almost anything now, except porn or politics. You won’t find the Miami Herald in the Weekly Packet,” said one client, Fabiano Sánchez. “But if you want to be informed about the world, then you can be. There are no mysteries anymore.”

But there are limits. The Weekly Packet makes for a very passive experience. It is, of course, close to useless for blogging, social networking and other interactive – and politically dynamic – forms of communication. Driven by memory size rather than processor speed, it brings with it an emphasis on storage rather than activity. This is also evident in the very different Cuban use of Wikipedia, which many people download in bulk packages of two to five gigabytes and keep on their mobile phones so they can use it without being online.

“I last used the internet two weeks ago. The last time I went on Facebook was two years ago,” said Luis Daniel Canetti as he discussed the problems of the Cuban web with friends at the FAC culture centre and nightclub. “I have access to a line, but I don’t use it because it is too slow and expensive.”

Prices are so high – and power cuts so common – that the most useful mobile phone application is the flashlight, quipped his friend José Alfredo Carreon. “In terms of schools and hospitals, what we have in Cuba is great, but we need to go a step further. We need to contact other people in the world. We need access.”

They and many others hope that US telecom companies can now help to upgrade the Cuban system and make the internet faster and cheaper. Whether it also becomes more accessible will depend on the government’s willingness to allow citizens a more interactive experience, for example by unblocking Skype.

Most people are hopeful this will be the case, although they expect change to come slowly.

For Fernandez, the provider of the lucrative Weekly Packets, it cannot come slowly enough. “I guess my business will be badly affected by the new announcement between Cuba and the US,” he said, when asked about the prospects of people downloading their own films - and perhaps even having to pay royalties. “I want change too. I just hope it will take several years.”