First off, why would you want to build content-rich websites? The short answer is "Because it keeps people on your site for awhile, it makes them come back, and they tell their friends about that site."
But why? Well, for one thing, people will stay on a content-rich site because it takes awhile to read an article or two. Thus, while they're reading the material, their peripheral vision (off to the sides) notices little ads that happen to surround that articles.
And if people start to realize that a certain site has good content that they like, and in particular, different content that constantly changes and is updated, then they'll check back to see what's new.
The worst thing in the world to have is a stagnant website that never changes. People will visit it exactly twice-the first time to check it out, and the second one to see what's changed-and when they find out it hasn't changed, they most likely won't come back. Ever.
What are Content-Rich Google Adsense Websites and Why Have One?
A content-rich site is one that has lots of informative articles up at it, usually centered on a theme. Most sites can't quite pull off being WikiPedia, so they specialize. For instance, you could do a site for dog owners. Possible articles on that site would cover:
How to figure out what kind of dog you want
Where to get a dog
How to deal with a puppy
Life stages of a dog
House-training puppies
Dog training
What to feed dogs
Whether to get more than one dog
How to socialize dogs with other dogs and with cats
Exercise needs of dogs
Training dogs to do tricks
Treating fleas
Common dog ailments and when to go to the vet
Dog nutrition
Taking your dog on a trip
Getting a pet sitter or boarding your dog if you don't take him on a trip
The articles you'll want to have on your site should be short enough so that someone can read them in about 5 minutes. This means you want to stick to articles of 250 to 750 words, with 300 to 600 words optimal. To give you an idea, a single page in a published novel has about 300 words.
Of course, your real purpose in putting up all these nice little short articles and changing them out frequently is not to just put information out into the world. It is to have a site that people will come back to so that they will see the Google AdSense ads, and click on them, and then you will get checks in the mail.
