Anywhere you go, people have started their own enterprise by putting down a parasol and a table. When you want to make a phone call but don’t have a phone or are out of credit, you can make one here for 20-25 naira. These guys told me anyone can now start a small business here selling phone calls and cards.
Another great example of increasing value by number: the more there are available, the more it becomes a truly useful service that fills up a need. The whole question of personal possession is perhaps less relevant when you can always use a phone to make a quick call.