There's still a lot of cases where it's very hard for even a consumer-facing US-based web startup to get traction in another country, for language and cultural reasons. Japan is a particularly notable case; it's often said that companies without an office in Japan never succeed there. Some examples:
Pixiv vs. DeviantArt
Mixi vs. Facebook
Nico Nico Douga vs. Youtube
China is an even more extreme case, though that also has problems of corruption, legal wrangling, censorship, and so on.
Pixiv vs. DeviantArt
Mixi vs. Facebook
Nico Nico Douga vs. Youtube
China is an even more extreme case, though that also has problems of corruption, legal wrangling, censorship, and so on.