Google has agreed to settle a lawsuit in which the Lane's Gifts and Collectibles online store had accused the search engine of click fraud.

Under terms of the settlement, Google has promised to revise the terms and conditions of its AdSense pay per click advertising programme. Where the company previously forced advertisers and publishers to file click fraud reports within 60 days, Google has now abandoned this filing window. Advertisers are allowed to challenge advertisings dating back to 2002, when Google first launched its AdSense programme.

Advertisers that successfully challenge past clicks will receive credits that they can apply to the purchase new Google ads.

The search engine is unable to predict how much money advertisers could end up reclaiming. The total cost of the settlement including attorneys fees are capped off at $90m, Google said.

The settlement has yet to be approved by the judge presiding over the case.

Click fraud occurs when a person or script clicks on pay per click advertisements for financial gain. Perpetrators typically are competitors trying to increase the cost of a marketing campaign or website operators attempting to increase their site revenues.

The scam is controversial because Google too benefits from it through the commissions they charge for their advertising plans. Critics claim this gives the search engine an incentive to turn a blind eye to the practice.

Google last year in May won a lawsuit against the Auction Experts website, which the search engine alleged had raked in $50,000 by hiring individuals to click on advertisements on its website. The search engine was awarded $75,000 in damages.