Ideas are for sharing. Ideas are for stealing. Ideas are not for hoarding.
Ideas in your mind are like little infants - they are underdeveloped and have a lot of potential.
Most of the time great ideas don't come from one mind in solitude, but by interaction with other ideas, feedback, and one's environment.
If you have a business idea, don't be afraid to talk about it. Nobody is going to steal it. The much more likely outcome is they will help you refine it or refer you to someone who knows a lot about that topic.
Do you really know anyone who will just stop what they're doing and dedicate their time to stealing your idea?
If you do, good for them! Ideas are easy. Execution is hard.
The more you share your ideas, the more people share their ideas with you. The more you share your ideas, the more people want to work with you. The more you share your ideas,the better your ideas get. The more you share your ideas, the better you get at separating the good from the bad.
Sometimes it's scary to share your ideas. I know that for sure. That's just another great reason to practice sharing them. Then it becomes less scary and more automatic over time.
P.S. Speaking of sharing ideas - THANK YOU to everyone who responded to my 10 business ideas challenge. Lots of creativity! Hope you enjoyed the exercise.*
Shout Out: A book that has influenced my thinking on ideation is Where Good Ideas Come From by Steven Johnson. He largely dispels the myth of "eureka" moments and argues instead that good ideas come from a much more social, interactive, and iterative process. Recommended reading.