Should we build a "Should We Build ..." service? A service for validating business ideas?

I was just thinking the same thing, but it's a bit like kickstarter without the cash pledges. Which means all someone has to do to endorse your idea is click a button (potentially), which is no means an intent to buy the finished product.

Secondly I'd be pretty pissed if I put my idea up on a service like this, demand for it skyrockets, then someone steals it and develops it before me.

There are differing opinions here on whether this is a good way, but give it a shot!