From my observations in Kumasi, Ghana and Kabul, Afghanistan (where I worked for a telco) having a basic cellphone and a cheap top-up plan is nearly universal. Prepaid SIM cards are sold on almost every street corner and the Facebook-enabled bundles are extremely popular.
After food, water, and clothing, family and business communications are the next most important need.
I would make a great ted talk. How cheap mobile communication is changing life in remote villages.
From own limited experience, I was struck by how expensive slow internet access was in the third world around 2008 (two years backpacking South America and South East Asia). The average local could not afford it. I could barely afford it. I remember for instance a Internet cafe in a small mountain town in Bolivia charged about $10 dollars an hour in 2008 (I guess it was internet by satellite).
I hope things have changed. Any internet access (however limited) would make a big difference to the poor.
The punchline is that when yo look at earth from space, the places that don't have visible (artificial) light are the places where innovation is happening, leapfrogging legacy wired infrastructure.