Twiplomacy recently came up with an excellent annual study of how heads of state and governments use Twitter. The study was done on 793 Twitter accounts based on data available until May 1, 2016.
Below is an exploratory interface we at Gramener built for a selection of fields from the same data. Each bubble is a twitter handle arranged by 'Continent' by default. Clicking on a bubble shows the connections for that particular handle. You can also rearrange the bubbles based on the number of Tweets, Followers, handles followed & the date of joining Twitter. Explore and have fun!