In print ads, measurements are made by number of column centimeters. It literally means the cost of 1,000 ad impressions. CPMs on different websites vary, depending on the quality of the advertiser and the target of the site's content. If a webpage has six graphics images and one text file, and a visitor requests for that page, that would account for seven hits for the site. This term is no longer used for accurate measurement of a site's popularity.
Page views are the more accepted metric.
If one page has four ads, that counts as four impressions. Home pages generally get more page views than other pages in the site, which is why more advertisers place their banners on home pages. A pixel is the smallest element that display or print hardware and software can manipulate in creating letters, numbers or graphics. An important metric for measuring website traffic, particularly in combination with page views. For example, total page views per month divided by unique visitors per month equals page views per unique visitor per month, an indicator of website stickiness.