Turns out * has some limiting factors [when serving 1 trillion page views a month]. Replace "*" with any piece of technology on the web stack.

There's not a single other company in the world (sans probably Google) that has to deal with performance problems on that level of scale. At that point, I can't imagine anything surviving out-of-the-box. Something has to give, even the language they're using (they're using a subset of PHP that they can run through a custom compiler to C++ machine code, to squeeze every possible CPU cycle out of the servers they have).