What about the opposite question. Do startups need to be in the US to be successful? And if so why? I'm sure there are non-US originated webapps that are popular in the US, but it seems the opposite tends to happen more often (Google, Facebook, etc etc...). Given that you can host your web app on EC2 from anywhere in the world with an internet connection as easily as from the US, what then are the barriers? My guess is that it is actually mostly cultural. If I write a webapp I am more comfortable knowing the target audience well. If it is a cultural barrier, then maybe the foreign founders don't really gain much from being in the US unless they are here to absorb the culture?