I think it's more the vision than just the idea that matters. Superficially understanding an idea and really "getting it" is different. In the end you're protected from most people by their own lack of knowledge, skepticism, small thinking, etc.
The people who are smart enough to steal your idea, in a way that would be competitive, probably have their own ideas or would be willing to work together.
If your idea is so obvious and easily understood that you have to worry about it being stolen, then you gotta wonder why someone hasn't already done it.
It's certainly true for my startup. I've been advertising my ideas for years, hoping someone else would do all the work, but in desperation I'm now building a company to produce the software I was hoping someone else would make.
Look at Google -- they tried to sell their algorithm so they could stay in school, but no one was interested, so they had to put up or shut up. If a bunch of people already thought your idea was a good idea, it'd effectively be a mature space.
'... if a bunch of people already thought your idea was a good idea, it'd effectively be a mature space. ...'
I'd modify that slightly...
'people already thought your idea was a good (MONEY SPINNER) idea , it'd effectively be a mature space. ...'
New ideas maybe easy to come up with but translation into a product is not easy. If you can see a new idea implemented & copy it you piggy back on the innovation of others thinking & implementing.
Compare for instance Flickr to say Zoomer. The later was developed post flickr & probably quicker. The point being Flickr came up with the wonderful clean url design, api design and concepts such as 'favourites'. It also showed there was a market. Zoomer copied lots of Flickr ideas without having to think, tinker & hack.
While it might not be entirely true, it certainly gives you an attitude that affects your behavior for the better, especially at early stages. From my limited experience, talking about your ideas to both laypeople and technical people can only help you.
Talking to laypeople helps you solidify and lets you practice pitching what it is that you're doing. When you're working at a company, you don't have to explain yourself very much. But when you say you're doing a startup, I've found that most people will demand more of an explanation. However, most people don't have the patience in everyday settings to listen to more than 2 or 3 minutes of it. This helps you whittle out the core of what it is that you're trying to build. Call it a functional spec cleaning, if you want.
Talking about your ideas with technical people might give you insight into different areas you're not as familiar with. The more that I read, the more I realized everything is inter-related. But it's hard to have that kind of breadth in this day and age of specialization--there's just way too much to know. Talking to technical people will often times help you make connections and leads to other technical fields that will help you get a feel for where else you can dig or if you're digging in the right place.
That said, most people won't steal your ideas for the same reasons mentioned before by others. Doubts and eagerness to point out how it might not work. Lack of vision, breadth and depth to understand the problem and implications. Lack of technical ability. Lack of time. Lack of motivation.
And after reading and talking to people, it seems like ideas end up changing. It's only when you're a bit bigger that you'd have to worry about secrets.
This entry asks a yes/no question, when there is no yes/no answer.
If you read the TechCrunch comments on FreeBase, there are a couple of people who say they had the exact same idea -- one even reserved "ifreebase.com." The idea is definitely not new. Facebook wasn't entirely novel either. There are a lot of factors that can make a good idea unprofitable, or a so-so idea a big hit (who knew what AJAX was before it was called "AJAX"?).
So, yes, your idea may be stolen if it's good. If your idea is obvious, there is a chance that people are just too lazy to implement it. The only way to win in either case, is to work damn hard on your idea until fruitition.
I'm halfway through Founders at Work and the conclusion I am getting is an overwhelming yes. The chapter on Hotmail is pretty illuminating -- nobody else they talked to thought web-based e-mail was remotely a good idea.
Almost everyone I meet(there are exceptions) is pessimistic of all my ideas. Which is lots of fun because you can tell they don't quite get the "whole thing" as you have in your mind no matter how well you explain to them.
Co-incidentally I wrote a post titled "Mere ideas have never been this useless" just earlier today. You can read it here: http://www.zaid360.com/?p=63
The best ideas are innovative and edgy. Any competitors will be behind the curve once they realize what you already know.
If your idea is good in a duh-obvious sense, then you can be damned sure someone else is already doing it or has done it. The way to succeed in this aspect is by doing it better where others have been lazy.
The people who are smart enough to steal your idea, in a way that would be competitive, probably have their own ideas or would be willing to work together.