In a companion survey of 500 of Africa’s most active Twitter users, the Portland-Tweetminster team found that the vast majority of those users — roughly 80 percent — use the service primarily for communicating with friends. But, fascinatingly, 68 percent of those polled said they also use Twitter to monitor the news, making Twitter a potentially effective, if still nascent, way to circumvent African nations’ generally highly restricted media institutions. And more than a quarter of the survey respondents said they use Twitter to keep track of job opportunities.Also worth noting: Just over half — 57 percent — of tweets, the analysis found, are sent from mobile devices. Which is actually a surprisingly low number, considering that, per a recent report, 433 million people in Africa — 53 percent of the overall population — currently have a mobile cellular subscription, while only 1 million (0.2 percent) subscribe to fixed broadband.