Nobody except google knows exactly how a fraudulent click is detected. Its defined as being an unnatural click but its hard to say whats unnatural. For instance if I search for insurance I could click on 6 adverts and then come back in an hour and again in a week and click on the adverts again. This is perfectly natural and google will be charging the advertisers for the clicks. On the other hand I have an insurance website and can click on my competitors adverts every few days for a week using the same pattern and this would be fraudulent clicking.
i am just looking for response based on those ppl's observation who have been in this industry for long enough to explain this exceptional terminology
I'd guess that all of the major PPC companies have their own definitions of click fraud, as well as methods of detecting it. Here's a pretty good definition from Allfeeds.com's ToS: "If we find that somebody is using any methods which will attempt to fool our system by modifying cookies or browser headers , autospawning of browsers, automatic redirecting of users, or any other technique of generating automated click- throughs we will terminate such account without warning and all unpaid money will be lost. Automated and forced click throughs: Autospawning of browsers, automatic redirecting of users, or any other technique of generating automated click-throughs is strictly prohibited. It is also prohibited to require users to click on the advertisers banner before entering any area of your website." Sam