1. Pay-per-action: This is however the more demanding type of ads where the advertiser pays the blog owner or blogger each time a visitor to the advertiser's site through the blogger's blog makes a purchase or order. If a suscriber to the blog comes and sees an ads and clicks on it, this will lead him to advertiser's site and if the suscriber or visitor now buys something sold on the site, the blogger is paid. The blogger placed the affiliate links and gets paid. Those offering include Amazon and Ebay. Direct ads post can be found under this also, where the blogger creates a spaces for advertizers to advertize and pay.
2. Pay-per-click: This is the easiest and the most popular whereby the blogger is paid immediately once a visitor or suscriber clicks on the ads on his blog. Can you beat that. This is the most lucrative. Pay-per-click is mostly made up of contextual ads. Contextual ads are ads that placed based on the contents or article on the blog. This is very effective in that it cause a suscriber to click because the ads placed to the articles thereby captivating the suscriber. Those that offer contextual ads include Google Adsense and Kontera. Text Link Ads (TLA) are similar to contextual ads only that they are placed based on a particular text in the page. Those offering it include Text link broker and Text Link ads.
3. Pay-per-impression: This is not popular but is great because just for advertiser's ads to appear on your blog, you are paid. This is just for the ads to feature on your blog. This type also pays the blogger depending on the number of ads placed. This means that the higher the number of ads, the higher the money flow. Those offering this include TribalFusion and FastClick.
Money tools for blogs are enormous and if utilized, one can see himself riding to the crest.
Keep you posted.