Dilma Rousseff (@dilmabr) of Brazil followed Medvedev with more than 1.7 million followers. Argentinian president Cristina Fernández (@CFKArgentina) is ranked 7th, with almost 1.5 million followers. The heads of state of Colombia (@JuanManSantos), Mexico (@EPN) and the United Arab Emirates (@HHShkMohd), made up the rest of the top 10.
While the number of states represented on Twitter rose, several countries stopped using the social network in 2012. Denmark and Ireland for instance let their accounts go inactive, the study said.
"One world leader who experienced a change of heart toward social media was the U.K. prime minister who, in October 2012, finally adopted a Twitter handle in his own name @David_Cameron," the study said. He is ranked 23rd with almost 190,000 followers.
The Middle East also saw a rise in heads of state that joined Twitter. In 2012, five out of the top 15 heads of state using Twitter were Muslim or came from Middle Eastern countries, the study said. "Arab Spring players such as Libya, Tunisia, and Iraq also had their heads of state adopt Twitter, and new government offices in this region included Qatar and the Presidential Palace of Afghanistan," the DPC said.
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