For ideas, there are patents. If somebody tells you to sign an NDA because they haven't got the patent yet, they're being naive. Assume their idea is really brilliant and technically innovative. They're busy patenting it, but tell you under NDA. You tell your friend Sue, who goes and rolls it out before they do. Well, now they can sue you for the billions they will never make - good luck with that. But they can't sue Sue: she never signed anything with them, and they don't have a patent. If there's really a "secret sauce", patent first, talk later. Generally, though, there's just ketchup.

I've also seen too many NDA's that include some sort of "rights grab", such as "any ideas that come up during our discussions belong to the company."

I wish independent developers would stop signing anything that is put in front of them. It makes me seem quite unusual in the industry, and often means that the first 45 minutes of a meeting is spent explaining why I don't sign NDA's.