For most tech companies, expansion is all about country-by-county localization. When your service requires a city-by-city approach, the operation can be far bigger and more complicated. To find out what such a granular approach to expansion involves, we spoke to three companies at different stages in their growth_but all focused on conquering the world, a city at a time. Uber Having raised a total of_$1.5 billion from investors, 21st Century taxi company-cum-'urban logistics platform' Uber is rapidly_expanding around the world. Beyond North America, Uber has only just got started. It's active in a total of 42 countries but mainly just...