For politicians, Twitter has become a "very powerful channel to broadcast messages," says Matthias Lüfkens, author of the "Twiplomacy Study 2014," which examines how foreign ministers, their offices and heads of state are using the social networking and microblogging service.

"It has become an indispensable channel for digital diplomacy," he adds.

US President Obama, Twitter's most "popular" leader, has more than 48 million followers. He was one of the world's first leaders to join the social network in 2008, and since then, many more leaders have jumped on the bandwagon. More than two-thirds of heads of state and government in the world are on Twitter, according to the Twiplomacy study.

Obama holds the record for most retweets by a leader.

Connecting with other leaders

Twitter isn't just about posting statements and updates. It allows global leaders to connect with their peers. And in the world of diplomacy, mutual following is very important, says Lüfkens. That's because it sends a message to the public that leaders are interested in seeing a peer's tweets in their feed, and it also allows two leaders to send each other private (direct) messages.

French Foreign Minister Laurent Fabius is the most connected with his peers on Twitter, according to the Twiplomacy study - 91 of the peers he follows also count him among their followers. Sweden's foreign minister,Carl Bildt is also very popular in the diplomatic community on Twitter.

"(Bildt) is really the best digital diplomat," says Lüfkens, noting that the Swedish foreign minister tweets himself, using the platform for some personal updates too.

Digital diplomacy at work

The growth of diplomacy via social networks like Twitter allows the public to get a better view of how diplomats interact with each other - via mentions, retweets and replies. For instance, these tweets on the Ukraine crisis by Austrian foreign minister Sebastian Kurz and his Latvian counterpart:

But it doesn't mean the public will be getting tweeted updates from their private meetings and negotiations, says Lüfkens.

"It just makes [diplomacy] more public, more visible and more accessible for us," he says.

But not everyone is so enthusiastic about that.

"It's a problem for heads of communication if the foreign minister tweets without consulting their staff," Lüfkens says.

And that can lead to an international spat. A good example of such a dispute took place earlier this year, following this tweet on Ukraine from the Russian Ministry of Foreign Affairs:

Then came this response from Swedish Foreign Minister Carl Bildt:

According to the 2014 Twiplomacy study, the tweet by Bildt wasn't checked by his staff. So the tweet in response from the Russian Ministry of Foreign Affairs wasn't so surprising.

It can be embarrassing to have to admit that you were wrong in public, but it is probably worse if you are a high-level diplomat. But whether it's international friendship or a public spat, diplomats on Twitter are allowing the public to see their interactions in a different light.