Cell Phones in the streets of Colombia

At Bogotá and other cities of Colombia that I visited recently - Medellín and Cartagena de Indias - I saw something that I found very useful and interesting. Every downtown corner has 3 or 4 persons offering the use of cel phones for between 150-200 Colombian pesos - 1 dollar approx. per minute. Before seeing this at Colombia, I had thought of it when I was in need of a phone to make an emergency call or report myself to friends when I was lost in a city. Of course, you don´t see many public phones around. Conspiracy theorists like myself would say that this is all product of cell phones companies lobbying against public phones. Others may say that it is probably the other way round: once this market for short phones calls emerged, there was no longer need for public phones and, thus, the project of installing public phones was cancelled. I don´t know what is the proper explanation but, in any case, I found it interesting.