Impressions Fraud

A large number of impressions, without the accompanying click on your ad - if you notice that there are a lot of impressions (views) of your advertising, this could indicate impression fraud. Impression fraud is artificial inflation of your ad impressions that may cause your ad click-through rates to drop below the Google minimum and your ad will be disabled. Until you realize this, your competitors have free reign to use your keywords, sometimes at bargain prices.As well, your relevancy ratings for search engines may drop as they record numerous impressions, but no interest shown via visits to your website, which could lead to a shutdown of your campaign.— source: Pay-Per-Click Search Engine Marketing Handbook.