The question is a different question, hence the answer is different. C10k wasn't considering the option of new languages, this thread is. The same question could have been asked back then (although most folks wouldn't have considered using anything other than C/C++ for high-scale servers then). Perhaps the thing that's changed is more memory and CPU power has made the option of new (and less efficient than C) languages a practical choice for new projects. I know that if, back then, I'd proposed the solution to my product's scaling issues with network I/O to be : "re-write all 500k loc in a different language", I'd have been laughed at.