I'll address the one with which I have first-hand experience...

On 1/18/07, Drew Olson <olsonas / gmail.com> wrote:
> 2) Why are many mainstream organizations using Python rather than ruby?
> Is it simply an age issue (Python has been around longer)? Is it a
> performance issue? Is this changing currently?

In some organizations, the answer is "inertia". It's more than just
age; it's the combination of age, existing expertise, installed base
of code, and concern about maintainability (however unfounded - I've
found that Python programmers have no problem reading, understanding,
and maintaining ruby code). But as more agile and startup companies
start using ruby, two things will happen: ruby talent becomes
easy/obvious to find, and some of those companies become "mainstream".
And then, who knows?

-Alex