Google used to be a very small search engine with nothing more than some "sponsored by HP" ads or any other company. Suddenly in 2001 they had the fantastic idea of selling to advertisers highly targeted people to buy their products and services. It's called Adwords.
When someone searches for what you are selling, you ad appears immediately and you only pay for the results. This system is so good that it makes what Google is today. But online advertising is much more than just Adwords. Unless you have a very specific market and product to sell, you will find Adwords quites expensive and competitive to beat. Thanks to competition you can have access to other networks such as Adbrite, Bidvertiser, Chitika, Triond it self, Double Click and much more. If you want to know how big this internet market is let me tell you that all the networks combines offer you more than one trillion page views per month.
That's a lot of people looking at the ads and ready to purchase something! As you know there are two kinds of paying for online advertising: CPM which means per 1000 impressions, PPC that means for every click and finally the CPA where you only pay when you sell. Both CPM and CPC and very old and too much talked about. CPA is not mentioned very much because it's here where all your website marketing and selling performance is tested and most webmasters are not good enough to make a living based only on CPA networks because the website doesn't convert.
With CPA advertsing you can see exactly where you are having a hard time making a sale and this way you learn quickly which pages should be improved! Too bad most webmasters do not know this... www.cj.com is a great place to get top class products and services most of them from very well known companies such as Yahoo! Now if you are an Advertiser and you don't like Adwords, this is a good place to advertise provided you are a big player, if not you can always join another CPA like Hydra Network. You must be approved first. After that you can never lose because you only pay when you sell. What could be better?