I personally research Twitter and message boards the way you described it for "blogdia". But I don't think there would be people / wantrepreneurs willing to pay for such an app.
Instead, why not doing a private / paid newsletter for that? Or a site where wantrepreneurs can buy your market research about a specific idea. And only a limited number of each idea can be sold in order to increase the perceived value of it.
Instead, why not doing a private / paid newsletter for that? Or a site where wantrepreneurs can buy your market research about a specific idea. And only a limited number of each idea can be sold in order to increase the perceived value of it.