From a post a couple years ago:
One of the principles I have followed through my career as an entrepreneur is an openness to talk about the business I am doing. I have found that this has more rewards than risks. Yes, there is a risk that someone may ’steal’ an idea but if it were that simple to create a replica, why bother doing it in the first place!
For me, the biggest reward is that talking to others helps me refine the way I think about what we are doing. The best ideas come when someone challenges what we are doing or asks a question on a track which we may not have thought much about. To get the right inputs, it is important to be willing to share what one is doing. Openness gets you more than you have to give.