There are a lot of companies forming these days who are trying to create a marketplace for internet leads. I.e. they will sell you customers. They are trying to re-invent the Google success story.However, Google itself is at the limit of complexity that the market can bear. This comment on a WSJ article covering Google v. Bill Gates sums it up:
I run Revitalization Institute, a non-profit that's deals with the revitalization of communities and the restoration of natural resources. ...
Now, you tell me: What magazine, TV show, or newspaper could we possibly advertise in to reach a diverse, far-flung group of organizations and individuals? There's only one medium that works: Google Adwords. Granted, it's an extremely frustrating and very lengthy process to learn how to use it properly, but it's the only game in town for someone who's audience is so broad that the only way we can possibly afford to advertise is on a per-click basis.
The point is that if you are trying to create a lead marketplace, it has to be simpler to use than AdWords. Your customers should be able to buy leads as easily as they buy books on Amazon.