Google does a great job of describing Google SMS— it’s basically technology that meets the needs and infrastructure of Africa:
Most mobile devices in Africa only have voice and SMS capabilities, and so we are focusing our technological efforts in that continent on SMS. Today, we are announcing Google SMS, a suite of mobile applications which will allow people to access information, via SMS, on a diverse number of topics including health and agriculture tips, news, local weather, sports, and more. The suite also includes Google Trader, a SMS-based “marketplace” application that helps buyers and sellers find each other. People can find, “sell” or “buy” any type of product or service, from used cars and mobile phones to crops, livestock and jobs.