Google has made a small change to AdSense that may make a big difference in cutting out errant clicks and even your AdSense revenue. They’ve redefined the clickable region for Google AdSense from the entire boxed region, to just the text link. Google Blogoscoped has a mock-up of the difference in the regions.
Although Google has filters to detect outright click fraud, unintentionally clicking on an ad region may be a less insidious yet hard to detect cause of wasted ad dollars. Last year, Google and Yahoo got into hot water over allegations of click fraud and eventually agreed to an independent audit. Google also wound up paying $90 million in a settlement, a small fraction of any potential earnings from fraud, but a wake up call for them nonetheless.