The last decade has not only been a period of extensive economic growth in India but also a period of optimism about the bottom of the pyramid. Three principles of sustainable economic development have made a big impact on our work: creating the capacity to consume among the people at the bottom of the pyramid, supporting hightech with high-touch to overcome problems of infrastructure and education and rethinking products and services ground up to meet the real needs of the users. Mobile phones have been both a symbol of this recent growth and a partial cause. In our explorations for design of products and systems for sustainable economic development, we have often turned to the mobile phone as a platform of choice. As new technologies such as speech, touch, haptic and gesture interfaces are on the verge of opening opportunities for new designs, it seems to be an opportune time to re-examine these principles and learn lessons from past experiments.