Google Tests an Ad Idea: Pay Only for Results - New York Times

As Peter Drucker and others have noted: if someone is going to obsolete your product, it should be you. 

Google is experimenting with a new proposition for advertisers: if you don’t get results, you don’t pay.

The company said Tuesday that it would expand a test of a system that allows advertisers to pay only when an ad spurs a consumer to take an action, be it purchasing a product, subscribing to a newsletter or signing up to receive a quote from a mortgage broker or car dealer.

I have a hunch one or more other companies may have some interesting patent protection in this context, however.

Source: Google Tests an Ad Idea: Pay Only for Results - New York Times