Because it is helpful to think about exactly what intervention is needed to help mobile money expand (which may differ by country), I’m throwing here a few potential barriers (mostly based on my own experience in Kenya and Myanmar):
Regulatory barriers (India allowed it only recently because of this; in Myanmar it’s still ongoing)
Network effects: in Kenya I heard that an important reason it took off was that Safaricom had a very high market share (maybe near 70%?); in Nigeria I heard that the fragmentation of the telecommunication market is one reason it didn’t take off. I’m not sure if more countries are similar to Kenya or Nigeria, also these are all anecdotal. One interesting thing though is that lack of competition in Kenya may have contributed to the high charges (though there is more competition now including from mobile carriers and banks).
Lack of trust: people may not trust mobile carriers or mobile money agents. Probably less of a problem in a close knit community where agents are shopkeepers. Also, lack of trust in banks is a common problem in developing countries but I have no idea about trust on mobile carriers/agents.
Existing alternatives already good enough: this has been mentioned to me in Myanmar, that the traditional “hundi” system of money transfer works well and is cheap which may dampen adoption of mobile money. If that’s true then mobile money wouldn’t contribute much anyway, but I’m skeptical since mobile money is really much more convenient. (Also it can be used as a savings tool like a checking account, and the poor often face savings constraint too, but I’m not sure how effective that will be; interventions that tackle “self-control” have worked well on this so such elements might need to be bundled in order for mobile money to help with saving)
The intervention I had in mind when writing this post was joining a start-up that has been working on this and has been seeing good results so far: http://www.jefftk.com/p/leaving-google-joining-wave
Wave is really good! (I use it) Another thing one can do is to work for some mobile money company in a developing country to design products that benefit the poor (e.g. saving, credit, that I mention in the other post), like the American guys I met in Myanmar’s Wave Money (but they are still early stage and has many challenges before having an impact). (Not suggesting you should do it though—involves moving to a developing country etc., and could be much less likely to succeed due to regulations etc.). BTW this is the mobile credit scoring company I had in mind: http://tala.co/.