A good tool to own once you manage huge ppc campaigns, it's a web service for investigating adwords fraud, you will assume this can be atiny low issue however some advertisers are whining that is up to forthy procent adwords fraud.
It uses a machine learning system to find perennial adwords clicks on your ads.
It has some limitations as it only interracts with adwords and does not filter the clicks before, but any software will do this
Adwords fraud, and false clicks performed on our ads. We reduced the budget for AdWords up to 25% procent, which is huge