PPI or the Pay per Impression model used in online advertising is more commonly known as the Cost per mille or thousand impressions. Many of the website tries to get the pay per impression traffic at their website to promote it better and reach out to the target consumers. in CPM, the advertisers determines the cost of every thousand impression by estimating the click through rate but in PPI it is the fixed amount that the advertiser needs to pay to the publishing network irrespective of the click through rate.
In order to get Pay per impression traffic the advertiser needs to invest in banner ads, popunder ads, popup ads and other kind of display media ad. In this kind of campaign the advertiser pays for fixed amount for ever 1000 impression of the ad. He needs to pay irrespective of the click rate he gets on those ads. In order to get good PPI traffic the advertisers can buy the traffic through a good online media company that can provide him the same. They can design the PPI campaign and can publish the ads on the good ad network so that the website is able to draw good traffic through those ads