[kazinator]

StackExchange itself has one such as site: programmers.stackexchange.com. That's about programming-related questions different from StackOverflow.

There is also CS StackeExchange for those open-ended questions that are in the area of theory.

Personally, I recommend good old Usenet. comp.programming newsgroup and others.

[manojlds]

Is this answer being down voted? Programmers SE is a good suggestion, and allows more open ended questions.