Using wikipedia as such a large reference that a significant portion of a book is paraphrased and even more so that word for word contributions were found even through editing out the copied work suggests a lack of knowledge as well as laziness in the writing of his book.
That's better than the Long Tail, which was just an unintentional work of fiction due to it being based on data from faulty third-party analysts. At least most of his Wikipedia info is probably accurate, and not essential to the rest of the book.
This means that all the copies of the book that have been printed so far are infringing the Wikipedia copyright. Fortunately, there's no physical-world equivalent of DMCA that allows Wikipedians to send an infringement notification to bookstores that carry it, requiring them to immediately disable access to the infringing material. But does it entitle Wikipedians (perhaps represented by the Wikimedia Foundation) to a share of Anderson's royalties as damages?
The funny thing to me is that given Anderson's message, he could reasonably have used many large, credited excerpts as an example of how great 'free' is.