If you are in Sudan it is a “missed call.” In Ethiopia it is a “miskin” or a “pitiful” call. In other parts of Africa it is a case of “flashing,” “beeping” or in French-speaking areas “bipage.” Wherever you are, it is one of the fastest-growing phenomena in the continent’s booming mobile telephone markets — and it’s a headache for mobile operators who are trying to figure out how to make some money out of it.