Steven Johnson has a good article on how he uses DEVONThink to write his books and articles. It is entitled “Cut-and-paste writing” and is in the March 2009 issue of Prospect Magazine. The url: http://www.prospect-magazine.co.uk/article_details.php?id=10646
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This video is interesting, DT is mentioned there.
https://www.youtube.com/watch?v=aXwxCzkHXLs#t=295.381264105
The link to the article is dead for me. But, here are three nice posts of his that I know about:
boingboing.net/2009/01/27/diy-ho … e-a-b.html
stevenberlinjohnson.com/mova … 00230.html
nytimes.com/2005/01/30/books … ought.html
Steven Johnson has written about DEVONthink and how he uses it, a number of times. The Tools for Thought article in the New York Times resulted in a nice sales blip for DEVONthink. 
He included a discussion of DEVONthink’s See Also assistant in several of his books, illustrating its use while he was writing the book.