Friends don't let friends plagiarize

This is from a blog of an author who writes fitness and weight-loss books:

http://www.bodyrecomposition.com/blog/2008/07/09/plagiarism-part-2/

The two authors were formally mutually exchanging authors. They did interviews with one another, product announcements and endorsements, etc. Apparently the other writer had used prior permission from Lyle as his reason to largely lift passages of his book for his own commercial material. That's whats tricky about all this; the prior instance was for a handout and not the new book. I think the whole situation really emphasizes how careful you need to be in an information economy. Certainly every book, ebook, DVD package, what have you, will have research from other authors in it. Plagiarism is taken very seriously in publishing, and all that boring English comp stuff about proper citations is critical. With the internet, there is no place to hide.