The basic idea is that you as a user can also participate in the ads bidding, and if you wins, the ad space will be replaced by a static image. To the website owner this is revenue neutral.
I'm not sure why it was discontinued. I still have fond memories of this service.
Most likely reason why it'd be discontinued is that it makes rest of the ads less valuable; so to speak.
People who can afford to & are willing to pay for something like this; tend to also be the type of people advertisers want to actually target: disposable income, willing to spend etc.
So instead of contributing to authors, you need to altruistically donate a large proportion of your money to Google in exchange for replacing a single kind of advert? Unlike some other Google products I can very easily see why this was discontinued...
You're paying for websites by viewing their ads. You're paying with unsubstantial things like attention (and bandwidth), which through Google and other Ad providers gets converted to cash for the website.
Google Contributor offered you to pay cash directly, instead of attention. The website owner gets some of that cash, same as they would if you were shown an ad.
Well, if the revenue remains the same for the author, and it also doesn't decrease for Google, it is implied that their margin will have to also be paid by the person who donates, for else the calculation will not work.
The basic idea is that you as a user can also participate in the ads bidding, and if you wins, the ad space will be replaced by a static image. To the website owner this is revenue neutral.
I'm not sure why it was discontinued. I still have fond memories of this service.