Traditionally, advertising has supported free access to content on the Internet for majority of websites. Google has taken a substantial share of the advertising spent on the internet not just via their search engine but also through their Google Display Network.
How does Contributor work?
Step 1: Users select their monthly contribution rate (between $1-$3).
Step 2: Visit the participating sites. Part of the contribution goes to the website and as a reminder of your support, a thank you message will appear, often accompanied by a pixel-pattern where ads normally appear.
Some websites who are already using this include Mashable, imgur, wikiHow and the Onion.
Again Google continues to innovate and push the boundaries of what is possible. Instead of milking the existing business model that works so well for them, Google continues to experiment and challenge the status quo.