> Why would anyone want to do that?

Funny -- I had the opposite response when reading the headline: I can't understand why collaborative authoring isn't ubiquitous in the industry. One of my favorite parts of watching a blockbuster movie is the credits: I sit there as all those names scroll by just marveling at the accomplishment that this huge group of people collaborated on. ("What a privilege", I often think, "to be able to work on that team.") I am writing a novel now (mostly solo, sadly), but the best chapter in the book was co-written with my daughter. My creative juices run deepest when they are mixed with someone else's.