By L.S., D.H. and P.J.W. EVEN Luddites know that the largest internet firms reside in America. The upcoming public offering of Alibaba, an e-commerce giant, will drive home the point that China is catching up fast. But what about the rest of the world? The latest numbers from World Startup Report, a market researcher, gives an answer. Of the 50 countries they examined, 30 have at least one interne