Increasingly handsets have a default setting for Facebook
A third of young people regularly access Facebook and Twitter via their mobile, a new report has found.
The study, published by mobile research firm CCS Insight, found that access to social networking sites was driving the take-up of mobile internet services.
Facebook is more popular than Bebo, MySpace and Twitter combined, it found.
Its study - into mobile usage among 16 to 35 year olds - also found that the service most youngsters wanted on their phones was the BBC iPlayer.
The suggestion that Facebook is more popular than Twitter chimes with a recently published Morgan Stanley report on internet and mobile usage.
Compiled by a 15-year-old intern, the report said that teenagers favoured Facebook over Twitter.
"Teenagers do not use Twitter. They realise that no-one is viewing their profile, so their tweets are pointless," Matthew Robson wrote in the report.
He echoes the words of CCS Insight analyst Paulo Pescatore.
"Forget music and video downloads, social networking is where it's at and Facebook is king of the hill," he said.
The 24-36 year-old age group are those most likely to buy content on their mobile phones, the report found.
The revelations will be good news to mobile operators, desperate to fill some of their revenue gaps with the money to be made on mobile internet usage.
One third of respondents said they would like to see the BBC's iPlayer available on their mobile phones.
But people will expect charging models to be fair even when they are using bandwidth-hungry applications such as the iPlayer, said Mr Pescatore.
"The challenge operators face is balancing demand for these services with the bandwidth they consume. Networks are going to think carefully about how they charge for mobile internet access," he said.
There appears to be a gender divide when it comes to mobile internet usage with twice as many men as women accessing the web via their mobiles.
"It's clear that the industry could a better job marketing to women. It needs more than pink paint to succeed," said Mr Pescatore.
CCS Insight predicts that by the end of 2009 some 44% of mobile users will access data via their handsets.
In separate news, a report from research firm Juniper has revealed that the number of mobile application downloads will approach almost 20 billion per year by 2014.