They are quite often academics who are used to passing the information from their research to other researchers or interested Netizens via the net. Graphics are almost non-existent. The style manual link from the last tutorial is a good example of this philosophy. To these authors a small logo of his department and school is about all the fluff you'll see from them. They may use a table but not necessarily for style but as a good way to display his raw data.
Pros Supports all browsers.
Good navigation because although long, the documents are well structured. Most navigation is achieved using targeted links. Download quickly because there are few images. I can't think of any cons. This was my style for quite some time.