I don't have too many friends who code (unfortunately), but even then, whenever I get the chance, I try to involve people I know personally. They tend to care the most for what I do, even when they might not know quite a lot about the subject. I receive really awesome input that way and can improve my ideas, visions, UX, etc.

Also I believe in the Skateboard Principle, so for me, it is very important to share early on, receive feedback and deliver a better product.

depends, I fight regularly with a friend about "dasmerkendienie.com" but I don't get involved with the Vision it's his baby ... we basically fight about implementations :) ....