A frequent question entrepreneurs have when they are just starting their company is: how secretive should I be about my idea? My answer: you should talk about it to almost anyone who will listen. This includes investors, entrepreneurs, people who work in similar areas, friends, people on the street, the bartender, etc.
There are lots of benefits to talking to people. You’ll get suggestions for improvements. You’ll discover flaws and hopefully correct them. You’ll learn a lot more about the sector/industry. You’ll learn about competitive products that exist or are being built. You’ll gauge people’s excitement level for the product and for various features. You’ll refine your sales and investor pitch. You might even discover your idea is a bad idea and save yourself years of hitting your head against the wall.
In terms of the risk of someone stealing your idea, there are at best a handful of people in the world who might actually drop everything and copy your idea.
First of all, most people will probably think your idea is stupid. This does not mean your idea is stupid. In fact, if everyone loves your idea, I might be worried that it’s not forward thinking enough.
People at large related companies almost always think they have already built or are in the process of building all the good ideas – so your idea is either something they are already building (which is a good thing to discover early) or else they will dismiss it as a bad idea. (I have a personal diligence rule that when speaking to people at large companies, the facts that they tell you are very useful but their opinions about startup ideas no more valuable than any other smart person’s opinions).
In terms of speaking to other entrepreneurs, the vast majority are already working on something and are highly unlikely to drop everything and copy you. Even if they are in the idea generation phase, high integrity entrepreneurs wouldn’t copy your idea anyways.
VC’s will either not like your idea, or else like it and possibly want to fund you. They vastly prefer funding an existing team than taking an idea and building a team. The one risk is if they have entrepreneurs they are working with in a similar area (see next paragraph). Most VCs have enough integrity to disclose this and let you decide how much detail to go into.
The handful of people in the world who might copy your idea are entrepreneurs just starting up with a very similar idea. You can probably just explicitly avoid these people, although by talking to lots of people your ideas will likely seep through to them.
Even if your idea gets in the wrong hands, they will probably just get the high level “elevator pitch” which isn’t worth much anyways. Hopefully by that time you’ve developed the idea much further and in much greater detail – by talking to as many people as possible.