First, asking for an NDA to protect an idea signals that you think ideas matter. Ideas are the starting point. But ideas, in the end, are worth little. Everybody has ideas. I have at least 10 one-pagers in my Google Doc account. To prove the value of ideas, I will disclose one of my favorites from my one-pager archive:
InteractiveBumper (IB) aims to deliver targeted ads to one of the last remaining captive audiences: the person(s) behind you in traffic. In short, IB will deliver geo-targeted ads onto a screen located on the rear bumper of cars. For example, a car equipped with an Interactive Bumper is idling in traffic one mile before the entrance to a Wal-Mart. Wal-Mart, a customer of IB, has bought this "spot" so delivers to the back bumper a promotion for the upcoming store. The cars behind the IB, as well as the cars to right and left, will have ample time to register the message and decide to stop in at Wal-mart or not.
Any takers? It’s all yours. Reach out if you want more thoughts on the idea.
In short, I’m disclosing InteractiveBumper because execution - not ideas - matters. Forming a team, building a prototype and convincing initial customers to test and then buy the product are what matters.
Of course, if you’re past the idea stage and have compelling IP, than by all means request an NDA.
Second, and most importantly, people in the start-up community want to help. There may be a few cheats, but the odds are several magnitudes greater that you’re sitting across from an ally. The people you meet will think about your idea and give you feedback. And even better, they’ll look into their network and connect you with relevant people like future employees or potential customers. If you silence these allies with an NDA, they can’t do what they do best: help you push your idea forward.
So nix the NDA and instead bind people to disclose your idea. The more you do this, the more allies you’ll gain, and the more feedback and connections you’ll make.