One company is the broker, the exchange, a major placement vendor, and the software vendor for algorithmic trading (which is a black box anyway). On top of that, in order to trade, you have to show them your books so they know everything about your business. And finally there is the extortion as well, don't advertise against your own name, oh sorry someone else is paying more.

The whole thing is engineered to extract every last ounce of margin from the advertisers. However due to the duopoly of the two colluding players (they carefully don't compete with each other) there is no choice.

It's frankly absurd the situation we have gotten into with online ads. It needs significant regulation.