Click fraud is a very real concern for anybody who is doing pay per click marketing. Click fraud involves any artificially created click on your ad. A human being can create these clicks, or a software program called a clickbot can create them.
These clicks unfortunately cost you money.
The hard part is identifying click fraud. In order to do this you need to constantly monitor your campaigns, keeping a watchful eye out for any abnormalities. You need to pay attention to your campaign