According to the agency, Solberg is only rivalled in her "conversational" use of the social media platform by four leaders in Africa and South America, all of whom appear to devote hours to engaging with their followers.
A full 74 percent of the Norwegian PM's Twitter stream consists of replies to her followers. This compares to 95 percent for Ugandan prime minister Amama Mbabazi, 87 percent for Rwandan president Paul Kagame, 81 percent for Ecuadorian president Rafael Correa, and 75 percent for Rwanda's foreign minister Louise Mushikiwabo.
Solberg also shares the honour, along with Russia’s Dmitry Medvedev, of being one of the two leaders mutually followed by US President Barack Obama.
This is not the first time the Norwegian PM has won plaudits for her Twitter skills.
In February, she won the "best Tweet" category at Norway's Social Media Awards for a humorous, but also gently cutting, tweet to former PM Jens Stoltenberg.
"I can't find my special recipe for herring salad in the moving boxes," Stoltenberg tweeted to former Prime Ministerial staff before Christmas. "Does anyone remember it?"
Solberg quickly tweeted back. "Hi Jens, I have not found any herring recipes in the Prime Minister's residence :)".
This year's Twiplomacy study brought bad news to Carl Bildt, foreign minister of Norway's neighbour Sweden, who lost his crown as the world's best connected foreign minister on Twitter to France's Laurent Fabius.
Being mutually connected on Twitter, the study explained, allows leaders to have direct and private conversations with one another - in 140 characters (or less) at a time.
"A number of foreign offices have used this channel to reach out to peers and other influencers to set the record straight or to coordinate their digital outreach," Burson-Marsteller said in a statement.
Bildt, who told The Local in January that he had "been working with internet issues since the internet started", is an active Twitter user and tweets regularly in English.
The report added that the Swedish Foreign Ministry (@Swe_MFA) has made "a conscious effort" to make Twitter connections, unilaterally following 355 other world leaders.
When it came to the most followed world leaders, US President Barack Obama was far and away the number one with almost 44 million followers.
Pope Francis came in a distant second with 14 million followers. Indonesia's President S. B. Yudhoyono was third with 5 million.
To put this into perspective, 20-year-old Justin Bieber has 52.5 million followers. Sweden's Prime Minister Fredrik Reinfeldt, meanwhile, has none as he is yet to join the Twitter bandwagon.
Twiplomacy took the chance to praise Bildt for writing his own tweets. It also dished out social media cred to the prime minister of Belgium for chatting with followers on Twitter, and even discussing how he likes his french fries.
It pointed to the Finnish Prime Minister @AlexStubb, as an example of a thorough Twitter user. Stubb shares his athletic exploits, has a penchant for selfies, and even co-authored an e-book in Finnish about what to do on Twitter and some of his tweets were even put to music.
Belgian Foreign Minister Didier Reynders, however, was called out on experimenting outside of his mother tongue, after his first tweet in English said "i'm coming on twitter".