There are many ways an advertiser can advertise his website or products. But in most cases more than the advertiser the publisher is getting more profit. The reason is the bad picking of ad type for advertising. There are many things to watch out before choosing an ad network for advertising. Especially the ad format that the ad network offers, the advertiser need to check the behaviour of the need of advertisement and need to select the ad type according to it. Otherwise the money spend for advertise will be a loss. Here I am going to compare some ad formats.
CPM:
Widely called cost per thousand. That is for providing a thousand banner views the advertiser need to pay the publishers a cpm rate. The rate is generally between 1$ to 5$ depending upon the geographic traffic etc. In this case the more benefit is for the publishers than the advertiser because the ratio to get an ad click is 100:1 that is for 100 visitors 1 click will get. This means from 1000 views the banner gets only 10 clicks and more or less from it. So this type for advertising is not effective for advertisers.
Pop Up:
Pop under ad type, most of the visitors hated advertisement form. But this ad format is best for advertisers who wanted to get traffic for their website. The amount spending for advertisement on this format is low so most of the advertisers may like to advertise on this format. But remember this format is only good for advertisers who wanted only traffic for increasing alexa rank or other things. Not good for the advertisers who looking for product sales.
CPV:
Cost per view, another ad format which is somewhat same as CPM ad type but there is some difference in the case of money spend. The advertisers need to pay the cash to the publishers for all the banner views. But the cost is low, 0.0005$ to above or below is sometimes the cost for views. Anyway this ad type is favourite ad type for most of the publishers and best for low traffic websites and blogs.
CPC:
The best and the most recommended ad format for the advertisers. Famous ad networks such as Google AdSense, chitika, adhitz etc. are offering this ad type for advertising. Advertiser need to pay only when the ad banner get click. This ad type is effective for advertisers who wanted to advertisers for product sales. The cost may start from 0.03$ to 0.12$ per click depending upon the geographical traffic. Most of the advertisers create banners with complete information about the products so that the customers will able to know everything about the product from the banner itself. This ad network is not good for advertisers who wanted just traffic to the website.
So select the ad type and ad network according to the need. All the best.