Wireless data systems are only about 1 percent wireless in terms of the average broadcast length. If I send a message on my iPhone it will travel to a tower where it is converted to a land based signal and broadcast to other processing centers. The power used by these towers is typically between .5kv to 3.5kv(as much as 70kv on large towers) That's a lot more power than that small basket ball size unit could carry on board. Also I checked the winds aloft for Africa at 10,000 ft and it was 36 knots about 38 miles per hour. So let's say these babies get a 20 mile range (which is stretching it at best) one would have to launch a new unit every 31.6 minutes to establish a chain for communication. That's not even weighing in the aviation dangers of this device. The thin soft walls of the fabric are invisible to radar. An airplane would never see the balloons in IMC conditions. Having two hundred in the air at a time and launching around 48 per day would allow for about .00001 coverage Africa. To cover the whole land mass (using a 20 mile radius) it would take around 40,000 units with 1.9 million launches per day. I just don't see the efficacy of 720 million launches per year. I dont think people who have limited food and water could support this system.
Warning all math was done in my head.