InMobi, an independent mobile ad network, has released its May 2011 Mobile Insights Report for Africa providing insights on mobile advertising trends on the continent.

Data from the report shows that InMobi now serves 4.2 billion impressions a month in Africa, up 37.9% from 3.0 billion in February 2011. Key highlights of the South Africa data include:

° Growth in smartphone impressions was 34% for the period, with 223 million mobile ad impressions monthly now coming from smart devices.

° With almost 74% ad share, Samsung and Nokia dominate the market with RIM a far third with 13% share

° Android is present in the market with 9.7 million impressions monthly.

° Nokia remains the largest manufacturer with a 20% share, but it has lost 3.1 points in just 90 days to RIM (+3.6)

South Africa shows 36% higher share of impressions on smart devices compared to other Africa countries. However, the relatively slow pickup of smart devices in Africa is highlighted by the fact that South Africa smartphone impression share is nearly half the global average.

The report finds that Botswana, Ethiopia and Nigeria show the fastest mobile adgrowth in mobile markets in Africa from February to May 2011. Nigeria and South Africa maintain thetop two positions as the largest African mobile markets, and now represent two of every five mobile ads across the continent. The full report is available to download at http://www.inmobi.com/research .