Twitter said Monday in Barcelona it had become profitable, disclosing that its live messaging service is carrying 130 million daily tweets, or short messages, from its members.

The US-based company, which has been one of the fastest-growing social-networking services, said 40 per cent of tweets are transmitted by mobile devices, typically smartphones.

“We’re making money,” chief executive Dick Costolo said in Barcelona at the Mobile World Congress expo, but gave no figures.

Twitter sets a size limit of just 140 characters on each communication. Each tweet goes to a user’s mixed collection of followers.

Founded in 2006, Twitter has been slow to develop a sustainable business model, with its originators opposed from the start to heavy advertising for fear this would put users off.

Costolo has ushered in a more advertising-centred approach, partly focussed on charging companies to tweet. He said further products to earn revenue would be coming up this year.

Past statements suggest Twitter now has 200 million registered users worldwide, and newspaper reports say the company has told investors it hopes to build its market value to 8 billion-10 billion dollars.

Costolo told reporters in Barcelona that Twitter’s latest traffic record was set on New Year’s Eve in Japan, when it was handling 6,000 tweets per second. During key US sports events such as the Super Bowl, it has peaked at 3,000 per second.

Twitter was driving people back to watching TV shows live instead of using video recorders to time-shift viewing, Costolo said: “People want to talk about the shows with their friends.” He said the service was about to launch an instant translation facility. This would allow people to input a tweet in English and have it broadcast in Russian and other languages.