*Commission tracking and contextual advertising can be a very powerful combination.
Essentially, businesses bid on certain keywords and phrases, specifying how much they'll pay per click. Contextual advertisers sign up web publishers to host their contextual ads, offering a recurring commission associate program. The publishers place a small amount of code on their web pages. When the page is viewed, the code queries the contextual advertiser to see which ads to serve up. You might see different ads at different times, depending on who has bid what, how popular your pages are, and where you've placed the ads.