Is Python good enough for big applications?
Performance wise - Yes, certainly for web frontends. The performance bottleneck is always the database.
From the moment I have faced Python, the only thing I can say for it is "It is awesome". I am using Django framework and I am amazed by how quick things happen and how developer friendly this language is. But from many sides I hear that Python is a scripting language, and very useful for small things, experiments etc.
So the question is can a big and heavy loaded application be built in Python (and django)? As I mainly focus on web development, examples of such applications could be Stack Overflow, Facebook, Amazon etc.

P.S. According to many of the answers maybe I have to rephrase the question. There are several big applications working with Python (the best example is You Tube) so it can handle them but why then it is not so popular for large projects as (for example) Java, C++ and .NET?