I guess there are 2 types of NDAs that I encounter.<p>Type 1 is the paranoid startup who thinks its a good idea to NDA everything for fear of someone "stealing" their idea. 9 times out of 10 this kind of startup is simply too naive to realize their idea isn't that original. I never sign an NDA to hear an idea, usually its a waste of my time because the NDA is typically hiding a BAD idea.<p>Type 2 is the legit NDA. When you're working with a large organization, or being shown very sensitive documents. Or occasionally a stealth startup that has a celebrity team or mega funding, something that would instantly get publicized should word get out. I'll sign these but usually these types of orgs are comfortable enough to give you the gist of what they're protecting and why first, and often its accompanied by a contract which seals the deal regardless.