Google introduces "AdSense Checklist" to publishers viewing U.S. Help Center to help you make your way with AdSense. If your language preference is set to U.S. English, you'll find the checklist in the left navigation bar of Help Center. You can recognize it by a "progress bar," that help you identify quickly how many of the recommended steps you've completed, and the checklist will suggest which step you can take next.
The checklist is divided into five parts, offering basic recommendations, required steps, and tips to help you grow your account to its full potential.
When you check an item, you'll see progress bar update accordingly. This help you in several ways. If you're new to AdSense, you'll get a clear overview of what steps to follow to make the most of your account. If you're already an experienced AdSense publisher, you'll also have chance to revisit basics, and further develop your use of the program.
More Info: AdSense Checklist