I think most startup folks know this but funnily enough, we get asked this quite a bit.
Let me break it down – VC’s don’t sign NDA’s.
Let’s have Brad tell you why :: http://www.feld.com/archives/2006/02/why-most-vcs-dont-sign-ndas.html
I love this paragraph:
As an entrepreneur, don’t think of this as “arrogance”, think of it as “practicality.” Your friend the VC is actually trying to save you time and money. If you think you have something super secret that no one else should know, just don’t tell me about it. Oh – and check your assumption in that case – especially since the value is in creating the thing, not simply having the idea.