There's certainly some interesting projections - The US may still be the world's largest consumer... but China and India are going to be the fastest growing markets. Just sayin', you surely wouldn't want to compete in a mature market with limited growth, would you?
Another interesting observation - Alibaba is HUGE. Being the largest player, it is already larger than Amazon and eBay combined. And still, almost all the Chinese ecommerce sites run on its platform. If you're looking for the next eBay to truly capture the world's attention... well, you're too late. It has already arrived in epic style.
There's always space for one more though. Anyone up for conquering ecommerce in Africa yet? ;-)