According to official data, Dr Mengi's verified Twitter handle, @regmengi, had 1,020,530 followers from Tanzania and elsewhere around the world by yesterday.
Analytics firm socialbakers.com said Dr Mengi’s Twitter account is the 13th most followed account in East Africa, which makes him the most influential business leader on the social networking site in the region.
Active on Twitter since January 2012 with nearly 2,000 tweets, the majority of Dr Mengi’s tweets are directed at mentoring and encouraging young people to engage in ethical business conduct.
Mengi, who is Executive Chairman of IPP Limited and also chairs the Tanzania Private Sector Foudation (TPSF), also often comments on issues of socio-political relevance in Tanzania, including condemning corruption.
In Tanzania, Twitter is considered more of a serious social network compared to the other social networks such as Facebook and Instagram.
Past studies analyzing Twitter usage indicate that Egypt, Nigeria, South Africa, Kenya and Ghana are the top Twitter users in Africa.
In Tanzania, Twitter has also become a serious medium of communication, thanks to the rapid growth in the number of Internet users.
Latest statistics from the Tanzania Communications Regulatory Authority (TCRA) show that around 20 million Tanzanians use the Internet, mostly from their mobile phone handsets.
An official at Twitter Inc, Sarah Harte, when asked about statistics in Tanzania, remarked, “Twitter does not release market-specific numbers.”
She did however explain that globally, Twitter has more than 328 million monthly active users and more than 500 million logged out users.
Like Dr Mengi, other highly accomplished African entrepreneurs who are active Twitter users include Africa's richest man, Aliko Dangote (@AlikoDangote), Strive Masiyiwa @StriveMasiyiwa, Tony Elumelu (@TonyOElumelu), Vimal Shah (@VimalAfrica) and Chris Kirubi @CKirubi.