The blogger’s observation that this occurs in genre works is certainly true, but there’s much more: VC Andrews is the obvious example, as Lastowka points out, but there are also long traditions of jointly authored worlds in sf/fantasy, sometimes created by people working at about the same time (Thieves’ World, Wild Cards) and sometimes involving later additions (H. Beam Piper’s Fuzzies), not to mention all the tie-in novels (Star Trek and Star Wars being the biggest examples, but it extends much further, from Beauty & the Beast to V). Superhero comics, of course, have had multiple artists, writers, and pencillers for decades, and the form supports auteurism among fans even without a one-to-one author/world correspondence. The idea of romantic authorship is too useful to die; what it is that the romantic author is responsible for, however, may change over time and genre.