Google Revealing "Click Fraud" Numbers
A post on the Google Inside Adwords blog announces that you can now see the number of invalid clicks as a part of an Adwords report. The report can show you both “invalid clicks” and the “invalid clicks rate”.
Most people seem to be jumping on this as a number that shows the level of "click fraud" - people intentionally clicking on ads multiple times for fraudulant reasons. But that is not the complete story. For example, there are times when I've clicked on an ad, read the page, moved on to something else, and then wanted to go back to the ad landing page. Maybe another question has come to mind or I need to clarify some of the information on the landing page. The easiest way to get there is to do the search again and click on the ad again. Google counts this as an invalid click. They only charge for the first visit, they do not charge the advertiser again if that same visitor returns within a reasonable time period.
There are other sources of invalid clicks that are not fraudulent clicks. So, although this new Adwords reporting feature gives you some insight into the potential click fraud your Adwords campaign is experiencing, don't count these numbers as "hard" click fraud numbers without another source of information such as your landing page logs. (Landing pages I create always include a lagging feature that logs each hit on the landing page.)