Below is a snippet from the site/page referenced in the question. The report is often called an outline descendant report. Each descending generation is indented and numbered, giving it the general character of an outline.
Others have provided good overviews of the information the report provides, some explanations have been included in the graphic above.
Because they often contain almost too many names to count, lengthy reports, such as the example, were popular "cousin bait" in the late 1990s; they may still be popular in some circles.
I once bought a book of supposed early Pennsylvania Miller genealogies. I had hoped to really learn something. When the package arrived, it was little more than hundreds and hundreds of pages of these outline descendant reports. A lot of the entries were just names and generation numbers. From the lot, I mostly learned that Miller families seemed to favor the names John and William. :-)
Below is an example of a similar report generated by FamilyTreeMaker 2010 for Mac. You'll note a different approach to the style.
RootsWeb's WorldConnect generates an outline descendant report from its files on command (to a maximum of 10 generations). They call it a "Descendancy report." See, "Ancestor and Descendant Reports."