I don't understand why Quora seems to be a standard to some. It hides it's answers behind a registration wall and ask that you give it access to your Facebook profile on registration.

It's a creepy website from my perspective.

Perhaps the french version? http://www.google.com/baraza/fr/

Bandwith measures seems to be important, local infrastructure (lower ping), text-based access, ... many things to think of.

A lot of website use appeals when it has a local flavor. Quora and it's Silicon Valley answerers probably doesn't know how to answer the questions that many Non-US citizens might have. This has a lot to do with user base, and I don't see Quora marketing itself outside of America.