The marketplace of startups seeking investors, team members, mentors and advisers is huge...yet we hear over and over again from mostly the investors, the angels and the vc's that it is okay to share your idea without providing an NDA. That there is no value in an idea and because there is no value one should not fear sharing it.
This is utter bullshit.
The value that exists in an idea is potential value, it is like the energy that a boulder at the top of a cliff has, stored up potential within the context of the Earth - Boulder system that can do smashing results once the boulder hits the bottom. Ideas are the same way, except the potential is exercised in a distributed fashion within the people who hear the idea.
Also, angel investors and vc's are particularly clued into networks where they can take an idea they feel is good and then sprinkle it in the minds of people who can implement it in their network. So you get to share your idea with them and they get to have some team else where implement it. A year later you hear of a new startup that implements something like your idea and you don't put two and two together. This is why the only time you should be talking your idea to angels or vc's who you can't trust (NDA or not) is AFTER you've already gotten traction selling your implementation and those angels and VC's have come to you after having heard of how good your product or service is.
Take for example Mark Zuckerberg, now that the history of Facebook has been thoroughly aired out we know at the least that he was not thinking of anything like a social network when he was approached by the Winkolvos twins and had they not approached him he likely would not have been the person to build Facebook. In fact, he was busy building Facebook based on the Winkelvos twins idea when they thought he was building their service. He simply stole the idea and all it's boulder on cliff like potential and created his own implementation (since the Winkelvos twins couldn't do it).
Had they kept the idea close, learned to code and built the site themselves its possible they would be in Mark Zuckerberg's shoes but they didn't they decided to share it with Zuckerberg who promptly stole the idea and implemented it, converting the stored potential into real value. Without the sharing of the idea Zuckerberg would have likely graduated from Harvard instead of quitting to go found Facebook.
Every founder who is peddling an idea with an implementation is the Winkelvos twins waiting to get robbed by some Mark Zuckerberg waiting for a great idea that they can implement and see the value of doing so for. The risk that your idea is stolen if you share it has no analog if you keep it close. If you keep it close you are guaranteed that no one else is working on YOUR implementation, you don't know if any one is working on AN implementation of a similar idea at the same time but at least by NOT talking about it, you aren't spreading the idea around to potential implementors of the concept and that I believe is why it seems so many technologies seem to emerge from multiple sources in a similar time frame...it is an effect that arises from the loose lips talking about the idea and the idea traveling until multiple potential implementers are sufficiently compelled by its viability that they start working on implementations and then all of a sudden they announce similar technology near the same time, it is not coincidence it is the math of a meme spreading.
This is particularly true in the world we live in, no longer are your ideas immobile relatively stuck to the community of physical agents you consider friends and colleagues. One mention of your idea can spread to the other side of the planet in *seconds* thanks to the hierarchical communication medium called the internet. Your idea can be in the minds of thousands of potential implementors with the knowledge and money to begin the implementation and before you have any idea who you will have built your idea...some one else is already working on code because they have the cash to front development or can get that cash from some one in their network.
In fact, your desire to share your idea should be inversely proportional to the size of your network. If you are alone in a room, share away ...as no one can hear you. However if you have a very well networked facebook profile, you'd better keep shut as "your" idea will be the worlds in seconds of you stating it and those people who implement it may not know who you are or even know you originally sourced the idea that they are marshaling their resources to implement while you dream on about how you wish you could if you only had enough money or people with the skills to help you.
So if you've got an idea and you can implement it, do so with mouth tight. When your baby is ready to test on customers then talk about it with them, build traction and then after you've already struck gold other implementations have far less ability to eclipse your momentum. Do not share it with any one without binding them to not revealing it to any one and even that should not be trusted.
The irony of this advise is that I have not taken it, this blog serves as a record of dozens to hundreds of ideas ranging from quantum mechanics and the nature of reality to the similarity between genetics and object oriented programming to my theory on how to create dynamic cognitive agents. I've received mostly silence on their expressions in this medium despite the site getting a fair amount of monthly traffic and that has been troubling to me but now I realize what it means. As I've created technologies and then watched similar technology appear later in commercial products and services its hard not to draw a connection due to what was explained above. So, I am closing the book on sharing new ideas on this blog, I'll only share implementations from now on.