The study, called Twiplomacy and conducted by the public relations firm Burson-Marsteller, looked at the use of the microblogging site by heads of state and by governments and ministers of foreign affairs.
"Not a week goes by without a new Canadian embassy setting up shop on Twitter in English and French," it said.
"Ottawa, which was once described as a laggard in digital diplomacy, has now caught up with its peers."
But when it comes to personal Twitter accounts, Prime Minister Stephen Harper languishes in 44th spot among 50 world leaders, with more than 478,000 followers.
That's a far cry from U.S. President Barack Obama, who remains the most followed world leader on Twitter with more than 43 million followers.
However, the study found that despite Obama's huge following, he is not the most influential leader in the twitterverse when it comes to retweets. That honour goes to Pope Francis, who has 14 million followers on nine different language accounts.
"His Spanish tweets are retweeted on average more than 10,000 times each ... In comparison, Obama's tweets are only retweeted an average 1,400 times each," the study said.
Rounding off the top five on Twitter are Indonesia's President Susilo Bambang Yudhoyono, the White House and India's new prime minister, Narendra Modi, whose number surged following his election in May.
"He (Modi) is expected to surpass the United States White House account within the next days and is using Twitter as a power tool to broadcast his messages," the study predicted.
Foreign ministers, meanwhile, are using Twitter to create a virtual diplomatic network, the study said. France's Laurent Fabius, who has connections to 91 peers and world leaders, tops that list.
"It is interesting to see how foreign ministries have created large digital networks on Twitter where not every tweet is approved by lawyers and press officers," said Jeremy Galbraith, CEO of Burson-Marsteller Europe, Middle East and Africa.
"Corporations and CEOs can learn a lot from politicians on Twitter, in terms of embracing digital tools for communications and how to connect with peers and influencers."
The study also found that few world leaders are actually posting tweets themselves. Estonian President Toomas Henrik Ilves, Swedish Foreign Minister Carl Bildt and Finnish Prime Minister-designate Alext Stubb are among the exceptions.
"Twitter has become a powerful channel for digital diplomacy and 21st century statecraft," said author Matthias Lufkens of Burson-Marsteller.
"World leaders might not necessarily read the tweets addressed to them, but their teams certainly monitor the Twitter activity."
For the study, Burson-Marsteller analyzed 645 government accounts in 161 countries in early June.
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