[doomslice]

They sometimes (often) have "last look" -- so a bunch of companies compete to win an auction against each other, and then Google gets a chance to win against the winner of those. This means that Google can essentially maximize the profit they receive if they have a better bid, because they know exactly how much fee they can take without losing. Everyone else on the other hand, has to compete with _lower_ fees so they can win that first round of the auction.

[whimsicalism]

If that's the case it is blatantly unfair. I don't think it is any longer though.