We consider the problem of explaining and forecasting the volume of cellular mobile traffic in a long-term perspective. To this end, we create a model of a market with both economic and non-economic variables, viz. the state of the economy, the current price level and the penetration effect on the market in question. We measure these variables by using publicly available data and by applying income theories and by combining theories of demand and technology diffusion. Applying the model to three markets, viz. China, Italy and Sweden, we show that it performs very well in explaining and predicting the volume of cellular mobile traffic. Noting the qualitative differences between these markets, we conclude that the model has some universality in that the results are comparable for all of them