I like this idea, but it's a bit of a double-edged sword. Yes you can convince people for good, but there are also ways of doing this more nefariously. I can't think of much off the top of my head right now, but the whole DHMO hoax comes to mind, and that's a relatively innocent example.

Of course I'm not advocating that anyone stay in the dark - the more we know about this kind of manipulation the better we can be at both using it and recognizing it. But as with anything there's a bit of a fine line to walk here ;)