How do world leaders perform on Twitter?
As soon as US President Barack Obama started his own Twitter feed, followers flocked to his new account.
The president already had an official account, with more than 59 million followers, but it is run by his aides.
Heads of government around the globe have been increasingly using Twitter as a tool to spread their message and gain support for their policies.
There is even a term for this form of digital diplomacy: Twiplomacy.
Public relations firm Burson-Marsteller publishes a report with that title every year, analysing how world leaders fare on Twitter.
And its findings suggest the US president's official feed is already the most-followed account among the world's political elite.
As the leader of the Vatican, Pope Francis is also included in the list of Twiplomacy, and he comes second in terms of follower numbers.
But this figure takes into account the Pope's feeds in nine separate languages, which is not really fair on other world leaders, including India's Narendra Modi who is in third place in terms of follower power.
There are two important factors to keep in mind when considering the ranking of follower numbers. The population of a country is one; India's size in this respect certainly helps Modi's standing.
Another factor is the level of penetration of Twitter, as in Turkey where the micro-blogging site is hugely popular.
But the irony is that the Turkish President, Recep Tayyip Erdogan, who is the fourth most-followed world leader, is also known for his complicated relationship with the site.
During the anti-government protests in the summer of 2013 that shook Istanbul and the rest of the country, Erdogan accused Twitter of being a ''menace'' to Turkish society, because his opponents were fervently active on Twitter organising the demonstrations.
Since then, the site has been blocked temporarily on more than one occasion.
But size is not everything in Twitterland. Another crucial term of measurement to assess the presence of world leaders on the site is how actively they are using it.
Latin Americans certainly lead in this respect, with Mexico's presidency being the most prolific, tweeting on average 68 times a day, closely followed by Venezuelan President Nicolas Maduro whose feed boasts a daily average of 64 tweets.
But are they tweeting themselves? After all, that is the selling point of Barack Obama's new account. Most of the Twitter feeds of world leaders are actually organised by an army of press aides carefully weighing every turn of phrase.
Estonia's President Toomas Hendrik Ilves is known to be one exception, as well as Norway's Prime Minister Erna Solberg, who makes the occasional spelling mistake because of her dyslexia, as she admitted in a tweet reply.
But critics of Argentina's President Cristina Fernandez de Kirchner will tell you there are worse crimes than misspelling.
During a visit to China, Mrs. Fernandez de Kirchner's tweet mocking the way Chinese people find it hard to pronounce the letter 'r' stirred up a controversy with accusations of racism that made it to newspaper front pages in Argentina.
One way to avoid any risk of a faux pas or a misunderstanding on Twitter is not to have an account in the first place.
Among the G7 leaders of the world, Germany's Angela Merkel stands out as the sole example of a tweet-free leader.
Perhaps the German Chancellor finds 140 characters too restrictive for the long compound nouns of the German language.
And on a final note which might help to put things in perspective, no world leader heads the Twitter count of popularity.
That accolade goes to pop star Katy Perry, with Justin Bieber, another pop star, following closely behind.