“The disproportionate weight of US/UK income and the low growth of income from rest-of-world vs. the far faster growth of usage outside the US/UK means that the toughest nut for Google to crack is not penetration but emerging market monetization.
The disparity is enormous. US/UK revenue is on average $86/user/yr (2012) and rising. The rest of the world only manages $12/user/yr. That Rest Of World includes many wealthy countries such as all of Europe and Japan. So the problem for Google is that it has an order of magnitude less income per user in the part of the internet which remains unpenetrated and the trends show that they are not narrowing the gap.”