Click fraud is a technique used to dishonestly inflate the number of clicks on a Pay Per Click (PPC) advertisement. If clicks are made artificially, for instance by a website owner selling PPC adverts, it will earn the advertising vendor more money and cost the client cash.
This black-hat technique is also used by competitors of the advertiser, who deliberately click on PPC adverts with no intention of trading with the advertiser but simply to waste their marketing budget.
Unfortunately, this practice is difficult to prevent or penalise. When running a PPC campaign, marketers are able to track the number of clicks and the conversion rate from those clicks so that they at least become aware of when their PPC adverts are the subject of click fraud.