I cite everything I can when I post on this forum. Everyone has an opinion, but not everyone has an educated opinion.
His book is expensive, $70 USD for the paperback, though I noticed it just dropped to $46 USD on Amazon. Books are usually marked up 400%+, and the author gets a small sliver of that from a traditional book publisher, and quite a bit more if self-publishing. It's an industry where 1% of the authors earn 99% of the revenue.
I'm an authority on social status, and when I published my book (I'm trying not to get banned from the forum, but it's ISBN-13: 979-8429909592 if you want to have a look), I get paid peanuts for each paperback I sell. In fact, I make the same royalty on a $7.49 Kindle e-book as I do from a $25 paperback because they incentivize pricing e-books below $10.
So I guess you can say I research for fun. I haven't figured out how to make a career out of it yet.
