So glad I'm not involved in PPC anymore. We used to catch junk clicks all the time, from many different countries. One company I worked with was local and wanted very targeted local clicks. Nothing I could do could stop clicks from other states and countries, which were useless to them.

Don't get me started about Twitter advertsing. Want some followers for your business? Twitter will gladly send you tons of obviously fake profiles as soon as you get too many impressions without a click. Like profiles without real pictures and timelines consisting only of retweets.

You have to tolerate an accepted amount of cruft with any PPC campaign.