Most tweets were about football and in English, communications firm Portland’s analysis of over nine million posts from October to December last year showed.
Johannesburg is the microblogging site’s busiest hub on the continent with 344,215 tweets, while Soweto-based Orlando Pirates was also the most mentioned soccer club on the continent.
Neighbouring Ekurhuleni recorded 264,172 posts in the same period, and Cairo 227,509.
Tweets spiked after global peace icon Mandela’s death on December 5, but still did not overtake football.
Over 60 percent of the posts were in English, while Arabic came a distant second at 11.5 percent.
Only five percent of tweets were in French, with the most active city in that language, Ivory Coast’s Abidjan, recording only 56,054 posts.
A quarter of tweets were in other African languages, often South African: Zulu, Swahili, Afrikaans, Xhosa, Portuguese, Sotho and Tswana.
Information technology is growing fast in Africa, though social media activity on the continent is still relatively low.