I have seen a lot of conversations on CoFoundersLab on the topic of stealing ideas. We all wonder how to speak of our ideas knowing the risk that someone can take it and run with it. There is a fine balance between NDAs, etc. and getting the word out. We talk about how ideas cannot be protected legally but it is the HOW the idea is executed that is important. Ultimately, what I have taken from these discussions is that there is a wide spectrum of opinion on how to take your idea out to the world to get it off the ground. The opinions range from NDAs for all conversations to NDAs are useless - get your idea out there and focus on execution - people don't really steal ideas anyway... etc. I found myself landing somewhere in the middle: Get NDAs signed when getting into the details but forgo them when talking more broadly about the idea.
I for one love stealing ideas and nearly every idea in the world has been stolen. That's what capitalism fosters - competition. First to market hardly ever matters in the long run unless its an idea that is peer to peer. Who ever executes the best wins out.
The first class in my idea generation program is all about where to look and which ideas are best fit for borrowing. https://23startups.com if you want to learn the details of this method!