China scale

A pretty simple but striking juxtaposition: the size of the Chinese mobile internet market versus the US smartphone market. There are over 1.2bn mobile subscriptions in China, and though China is still a much less prosperous place than the USA, even the top half - the half that's using the mobile internet and buying 3G phones (almost exclusively smartphones at this stage) - is more than double the size of the US smartphone base. 

(Strictly speaking, I should put the Chinese smartphone install base on this too, but that data is rather less solid, and the point remains.)