Nobody’s going to steal your idea
I don't agree.  Mainly because I don't agree with the premise that ideas are worthless - something that is echoed around all the time.  Ideas being worthless is the lazy and easy way to explain to someone why they should get feedback on their idea.The reality is ideas do have value.  We've got a great idea for a new product, and we're not telling anyone about it.  That's because our idea has value and we don't want anyone else to make it before we do.  Come back to us in a year or two and I'll happily explain our reasoning behind this.If an idea is worthless it means it literally has zero value.  Value doesn't have to be a positive value, it can be negative as well.  Given 2 ideas, which of these would you rather develop:- A mobile phone for elephants- A service which sends you an SMS when your website goes offlineIf both ideas have zero value, it doesn't matter which one you pick when you set out.  The reality is if you are going to set out and make mobile phones for elephants you are going to burn through your cash a lot quicker, and have a much lower chance of ever making money and succeeding (if you measure success through sustainability and profitability).These two ideas are not equally worthless, therefore one has more value than another.  Two things with differing value cannot both be worthless unless they both have negative expected value.  Not all ideas have negative expected value and you easily build a case arguing that the SMS service idea has positive expected value.  "All ideas are worthless" is not true as all ideas have varying levels of negative/positive expected value.Sharing your idea is usually the right thing to do, but it does come with some potential downsides.  Just because it's usually the right thing to do doesn't mean it's always the right thing to do.Someone might steal/copy your idea.  It's probably a lower chance than most people estimate especially in the very early stages of startups.