> For backend/webservices, I initially tended to agree Go is a killer tool. But if you are a Python shop, why would I bring this into my stack instead of using PyPy (or soon, Pyston) for CPU-intensive tasks?

Two big things here, for my applications.

1. Memory. You mention CPU use, but memory use is even more critical for what I do. For game servers, for example, lower memory usage for an application can change the multipliers on how many users I can handle per server. This can make a dramatic (like 20x) difference in what you can offer users for free vs charging.

2. Static compilation. This makes a massive difference over Python in terms of catching and correcting problems at compile time vs run time.