This is cool. Twitter has teamed up with MTN Cameroon, a mobile communications company in that country to provide a way to cut costs for messaging. Users can send SMS messages and will be charged the same rates as always but they get sent as tweets and there is no charge for receiving them, Twitter apparently picking up the mitigated cost. Similar arrangements are already in place in Nigeria and Madagascar.
Twitter's service is made for the low-end handsets that dominate the mobile market in Cameroon and elsewhere in Africa. By setting the cost of receiving updates to zero, you create an instant medium for a new form of communication. This leads to increased efficiencies, better access to market data, propagation of memes, new ideas and most importantly--opens the door for innovation. It has the potential to democratize information flow between the internet-haves and have-nots.