Is an impression equivlent to a unique visitor to the site or a single hit? A. Impressions are equivalent to single hits. ie Page Impressions, where as Ads Impressions are equivalent to single hit per ad shown on your site. Is it possible that a site receives 100,000 impressions in a month but very few click? A. Depends upon what your site matter is and also more importantly on where you are placingyour ads. My guess is Site with 100K impressions should have avg. no. of clicks per day.