Tell HN: Creating a new advertising marketplace

Google, Microsoft, Yahoo dominate majority of the online advertising market. My question is why?

Looking at the very basic model, an advertiser wants to pay $X to a publisher to place ads. Therefore, publisher should get $x - overhead cost. But instead most of the profits are going to the Big 3.

Therefore, we should have a non-profit system that provides a marketplace for transactions and only charge overhead costs.

Therefore, maximizing profits for the publishers and advertisers.

Since, there is a big community of developers in HN, you guys should lead the charge.