A new study says South Africans and Kenyans are Africa's most active Twitter users and that the social networking site is rapidly becoming a key information tool across the continent.

Researchers analyzed more than 11.5 million tweets from specific locations in Africa during the last three months of 2011.

They found South Africans made more than 5 million of those tweets, twice as many as people in any other country. Kenya was next with nearly 2.5 million tweets, followed by Nigeria, Egypt and Morocco.

The study says the growth across Africa is being driven by the use of mobile devices.

It found that 80 percent of those polled used Twitter to communicate with friends, nearly 70 percent used it to monitor news and just over 20 percent used it to find jobs.

Africa's most prolific tweeters averaged between 20 and 29-years old, much younger than the global average of 39 according to the report.

The study, called “How Africa Tweets,” was conducted by two companies — Kenya-based Portland Communications and Britain-based Tweetminster.