Zygor claims that he doesn't break the rules because the addon is provided free of charge (which it technically is, it's the full guide which you pay for in the end). Whether or not this is true remains unclear. It's up to Blizzard to decide whether or not they want to take action against it.
Good luck with looking for an author.
P.S. I have a feeling that this topic might derail into a big discussion on the Blizzard guidelines again - let's try not to do that. As long as an addon is made public and is free of charge, there's no problem with someone paying the author for his work (which is then essentially a donation).