That is what I mean, people will steal the idea just as they would your bitcoins if they had the chance.
Any VC will tell you that this is wrong.
Have you ever started a business? Have you ever made a venture capital investment, or even received one?
The best thing you can do right now is build your idea. The second best thing you can do right now is post your idea. The worst thing you can do right now is post about "having an idea" and nothing else.