Ok that is interesting. I guess those affiliate revenues are lucrative. However, and not that this is regarding the original question, but taking this further,

Ok that is interesting. I guess those affiliate revenues are lucrative. However, and not that this is regarding the original question, but taking this further, I question how far a search company can scale if its revenue is affiliate deals. In some sense, they're captive to the pricing power exerted by their affiliates. Whereas a more numerous market of diverse advertisers have a lot less bargaining power to set prices, because their individual contributions are smaller and there's more of them. So it seems that's one reason why, if your main revenue stream is affiliate deals, that could be a bottleneck on your growth at some point.