When users of Google’s Contributor service pay, ads that normally appear on certain websites will be replaced with a banner that says “Thank you for being a contributor.” An oft-heard saying in Silicon Valley is that “information wants to be free.” Google is running a test to see if users feel the same way. On Thursday, Google started experimenting with a new way to let users contribute to web sites in exchange for removing – or at least reducing – the number of ads. The service, called Contributor by Google, has users give between $1 and $3 a month to sites like The Onion and Mashable.