I always get this tiring feeling when someone comes up to me to talk about an idea. Especially if it's one of these "fast talking" kind of people. Most of them involve some kind of "social X". Even more saddening is how the people that have these "ideas", have no clue how to market it, where profit comes from, and so forth.

I believe that the only time I've heard of a decent or good idea was from fellow programmers or designers, rather than "business men" or founders of small companies and claim they know it all. Then after they explain their idea, they expect you to invest 90% of your time on the product, promise you a certain ownership percentage (usually ~10%?), rather than paying a good salary up-front; so if it flops they didn't lose any of their time or had to invest any amount of cash. I believe something similar to this happened to some dude who then open-sourced the project. I forgot what project that was, it happened recently.

You can of course listen to anyone's idea, but as the article stated, the chance that it's not another dumb or over-done idea is usually very slim.