What is a quick way to get feedback on ideas?

I have many ideas of products I would love to develop, the problem is that most of them have been done before, are not feasible with my skill set, or they suck.

For the few concepts that get past my own vigorous self critique, what are the best ways of getting quick and immediate feedback from the world?

I would rather not post things here as I would rather not dump my hard analysed ideas to a bunch of anons on the internet (no offence) - am I wrong for thinking this?

If I email an infographic of my idea to investors will they give me feedback?

Are there any other strategies?

Thanks guys!