Found out about Google Contributor today
https://en.wikipedia.org/wiki/Google_Contributor
Pretty interesting idea. Users can out-bid advertisers as a way to remove ads, creating a market-based solution for removing ads instead of a subscription-fee-based alternative to ads.
In the implementation, Contributor bids for ad slots on the user’s behalf using the standard Google ad auction system; if the user wins the auction, the Contributor image is placed in the ad space, and the cost of the ad is deducted from the user’s monthly contribution. If the user does not win, the winning ad is displayed as normal and the user pays nothing for that slot.
The ad blocks, instead of displaying advertisement material, will, by default, display a thank you message with a pixel pattern. This pattern can be configured to contain cats or other patterns.