Ian Burrell: Is Murdoch's Twitter conversion just a flight of old-age fancy?

When Rupert Murdoch radically changed his Twitter photograph last week it was a signal of how seriously he was taking his social networking. Gone was the amateur shot that appeared to have been taken on his phone, showing him craggy-faced, chewing his lip and wearing a sweater. In its place was a professional portrait of a switched-on businessman in a shirt and tie.

The initial assumption had been that this new year's Twitter experiment was a PR exercise, an attempt to soften Rupert's image after a humble pie year in which his personal reputation has faced an onslaught unparalleled even in his own extraordinary saga. But in the space of a few days he appears to have been convinced of the power of the free online medium and rethought his strategy.

Having opened his account with comments about his holidays ("great time in sea with young daughters, uboating") and praising his Fox film empire for the family movies he was enjoying, he hardened his tone to talk about business and politics. He has used the platform for endorsing his favourite politicians, such as Michael Bloomberg ("New York's best mayor in memory") and, most significantly, the Republican presidential hopeful Rick Santorum ("only candidate with genuine big vision for country").

After initial amusement, Murdoch's every tweet provokes a flurry of analysis and brings thousands of new followers. Emily Bell, the former Guardian journalist and head of digital journalism at Columbia University, tweeted: "If @rupertmurdoch can endorse Rick Santorum with 140 characters on a free platform, not sure why he needs expensive newspapers anymore."

The same thought must have occurred to some at News International where Murdoch's British papers are trying to build a digital audience behind a paywall – a subject which obsessed the British media only a year ago but has been swamped by the phone-hacking scandal. It's little surprise that Wapping journalists such as Danny Finkelstein, Janice Turner, Caitlin Moran and David Wooding quickly became part of Rupert's 114,000 Twitter following.

Rupert's alleged interference in the editorial content of his papers has been a subject of contention. The publication of his opinions in such a manner will make it harder for his editors to ignore his views. He is not much interested in other people's tweets, following only 11 accounts (mostly News Corp related) and unfollowing Lord Sugar (to the peer's dismay). Most of Murdoch's Internet-literate children are reluctant to tweet (his garrulous TV presenting Australian daughter-in-law Sarah is a notable exception) but Rupert has suddenly embraced the format.

"There's a certain irony to the fact that whatever the message he is trying to convey, he is using Twitter to do it, a free media platform, when he has put much of his business's political content behind a paywall," says Stewart Easterbrook, CEO of media agency Starcom MediaVest Group. "When push comes to shove, people revert to the most effective, most immediate media opportunities. When someone invades a country they don't take over the poster sites."

Ben Ayers, head of social media at Carat, thinks the "powerful force" of Twitter has given Rupert a lesson in the audiences generated by free social media. "He may be impressed by the value offered by the free service and it could make him reflect on the roadblock that paywalls cause users of Twitter when content is shared."

A source close to News International's paywall strategy acknowledged the irony of Mr Murdoch's "late conversion" to using social media, given he paid $580m for MySpace in 2005 and sold it last year for $35m (£23m). "If he had this Damascene conversion five years ago he might have understood how to make money out of MySpace," he said. "But if the knockers are saying he's going to drop his paywall strategy and make everything free, I would not go along with that."

Ayers thinks the magnate is probably experimenting, looking for ways to generate greater profits. "He'll no doubt be interested in the interplay between social media and TV events, possibly sensing the threat to Sky's precious sporting rights posed by the new kids on the TV block such as Google and Apple who thrive off social media ecosystems. Most likely he's doing what most people are now doing – trying to work out what all the fuss is about."

But Michael Wolff, Murdoch's biographer, has another theory. He claims that the News Corp chairman and chief executive officer is now a marginalised figure, under pressure to cede power and delegate decisions to younger colleagues and his children. "Rupert is increasingly uncomfortable within his own corporation," says Wolff. "Twitter could be a kind of outlet for Murdoch's own frustrations."

The paywall strategists at News International may be hoping that it's nothing more than that.