I personally am very hesitant to sign non-disclosure agreements especially with those in the same industry AND new to my circles. Just my opinion, but the thing about ideas is that they are essentially worthless without the execution. No matter how 'great' or 'innovative' one might think their idea may be, entrepreneurs are usually too busy working on their own 'great' or 'innovative' idea to replace it with another. If the other person is not willing to risk some sort trust level of information then maybe you are better off moving on. If you feel the upside outweighs the downside such as you already have an established relationship with this party/ have validated this lead/feel you want to explore more, make sure the NDA goes both ways.