Sivers did a ted lighting talk about this: <a href="http://www.ted.com/talks/derek_sivers_keep_your_goals_to_yourself.html" rel="nofollow">http://www.ted.com/talks/derek_sivers_keep_your_goals_to_you...</a>
The best solution is to write the idea down. This will help you remember it later or develop it further. Writing helps you think. So, you might come up with more ideas while writing.<p>For Mac, I love the full screen mode on the iA Writer. There is no way to spend time formatting your text and no other distractions.
I really think this advice depends on the idea and the person. If I had a great idea, and more and more people kept telling me how great it was, I would be even more motivated to go out and make it happen. On the same token, if everybody told me it didn't make sense, that's the type of feedback you need to refine an idea, make it more clear, or even decide to scrap it. At some point you need some sort of outside validation or criticism<p>On the other end, I agree with the author it's important to spend a lot of time with your idea before you share it. 9 times out of 10 you haven't fleshed it out enough, considered all the angles before it's ready to share, and that's when an idea is really fragile