AdSense for content has evolved greatly since it was first introduced. Google adds new features on a regular basis in response to feedback from publishers and advertisers. Experienced website owners can visit the official AdSense site at https://http://www.google.com/adsense/ to learn all they need about the AdSense program and its newest features.
Be aware that the web page ad-rental market is about to heat up: Yahoo! is entering the fray with a product similar to AdSense called the Yahoo! Publisher Network. Details on the Yahoo! program are lacking, but Yahoo!-supplied text ads are currently found in beta form on a number of sites.
The next article in this series discusses the second AdSense program, AdSense for search, which lets you add money-making search capabilities to your website.