I have been worried about this thing that if I share my idea with some developer, he or she will copy that or may steal that and execute on their own. But after two years of struggle, I reached the conclusion, that no one can steal your idea. Here are some of the reasons:
1. Its not as close to their heart as it is to you:
Recently, I went to start up weekend and my idea could not go to the next stage but 18 others did. I worked with another team over the weekend which stood second. I know, what the team lead wants to do, he is not even a technical guy but I am not going to steal his idea. In fact, I am not going to steal any of those ideas or rather I can not because those are not as close to my heart as those are to their creators/inventors. All of them are doing big thing and that's not my thing man, I won't do that.
2. Big companies think, you are stupid:
Big companies or investors think, every best thing comes from their stores and whatever you are doing is worthless. I heard Mark Zackerburg talking at world economic forum to the question, "If you had not done Facebook, what you may have been doing?" He said, "may be something similar" and he extended his reply by saying, the reason why he did Facebook but not Google or Yahoo or any big name despite their abundant resources and workforce was "we felt the need for such a network more than any body, it was more close to our hearts than someone else." The response was amazing.
3. No one will pursue it leaving what he or she is doing:
On events like startup weekend or similar competition, every one who attends is involved in something. They just won't leave their stuff and start messing up with your idea while no body knows it will fail or succeed.
4. You think, you have found what is next big thing but let me know, you have found an average problem:
When I proposed my idea, I thought it is solving amazing problems and people will get to relax, save their time and blah blah. But the matter of fact is, you have thought an average idea which some one else is capable enough and with a high probability may be working on already. So get the word out of your mouth to the people to get feedback and know the worth of your thinking. Do not fear of getting idea stolen by some peer or someone.
5. Only similar ideas may get inspired:
Well in true sense we can not call this stealing but this is the only scenario which comes to my mind when talking of idea stealing. For example, I have this idea of attendance system, which sends an email to parents cell phone on each marked attendance of a student. I checked online and found some solutions in market, so I did not pursue that for this reason. At first I thought I have found an amazing idea which have not been identified and solved but it was not like that. On this weekend, I found a project which was RF based student attendance system that is closely related to my idea. Hence, if I implement my concept in near future and someone says that I have copied their idea, it will be wrong but since things are related so they can say. This is the only scenario when people may adapt someone's idea but its very rare.
So go out there speak loudly and see if you can hear echo, if you can, you are amazing.