The blog is promoting the book, "Pick Four" (not Linchpin).
Linchpin is actually really good though.
I agree. I've read most of his books but Linchpin has depth to it that the others don't. I've heard people remark they were "confused" with the message and had to re-read the book to digest it. It's just pure unadulterated Seth Godin, that's all.
I thought the post was promoting the "Pick Four" book?