A few days ago, I just received an email from google regarding its click fraud settlement.

Let me quote a part of the email

If you purchased online advertising from Google between January 1, 2002 and the present, you are a class member in a class-action lawsuit in the circuit court of Miller County, Arkansas. This notice is to inform you of the Court's certification of a class; the nature of the claims alleged; your right to participate in, or exclude yourself from, the class; a proposed settlement; and how you can claim an award of advertising credits under the settlement.

Upon checking the site created specifically for the settlement clicksettlement.com

...all persons or entities, together with any officer, employee or agent of the same, that purchased advertising on the internet from google on or after january 1, 2002 regardless of where the ad was displayed.... in order to participate you must submit a claim form via the website clicksettlement.com

There would be no refunds but rather, an advertising credit will be rewarded to those people who are part of the class-action lawsuit. So if you are one of those advertisers, you can avail it.

There are also other people against this like bruceclay.com.