This is one of the first genuinely original ideas that I have seen in a long time. You can create a site, use AdSense to drive traffic to it to see if your idea has merit.

This one little additional step lets you actually get into conversation with people visiting your site before you launch is very much lean startup.

Now as a developer building the product I can hear the objection you won't be able to get the product built if you keep getting interrupted. But you may be building the wrong thing. So this makes a lot of sense to me.