Modular Docs Part 2: DITA vs. DocBook
http://blogs.sun.com/coolstuff/entry/modular_docs_part_2_dita

Armstrong, Eric
Sun Microsystems
2008

Abstract:

When IBM decided to focus on topic-oriented documentation, it created the Darwin Information Typing Architecture (DITA), even though there was already a huge investment in DocBook. Moving to a new architecture was a decidedly non-trivial undertaking--both technically and politically--so it is worth an inquiry as to the reasons for making that move.