Cost Per Impression (CPM) - is an Internet advertising model used on websites, in which advertisers pay for the number of times an ad is show regardless of whether it is clicked on or not.
The style of campaign known as CPM pertains to selecting and targeting a demographic much like in PPC campaigns, but in this instance you are billed for each impression instead of being billed only for clicks. Impression-based campaigns tend to be very cheap; in many cases, you can have your ad seen thousands of times for less than a dollar. This also means that while your ad is running, you can usually monitor the statistics such as click through rate (CTR) and make any budgetary changes as necessary – before massive amounts of money have been spent. Impression-based campaigns are therefore ideal for those on a budget.
Google Adwords allows to you place text ads on websites that are part of their display network with Advertising Method Cost Per Impression Using A Cost Per Click Method = $1 per 1,000 impressions.
What is it? - Facebook ads are the ads that appear on the right hand side of every Facebook page. They usually appear below the section titled "People you may know" Cost Per Impression Using A Cost Per Click Method = $0.19 per 1,000 impressions
What is it? - These are the three little ads that appear on every Linkedin page right below the section titled "People you man know". They are located on the right hand side of the screen and are under the title "Ads by Linkedin Members".
Cost Per Impression Using A Cost Per Click Method = $0.85 per 1,000 impressions
As with Facebook, Linkedin provides an estimate of what should be paid if you choose the CPM purchasing model. They are currently recommending that I bid $2.06 to $2.12 per 1,000 impressions