When learning to drive, I often heard the phrase 'Do as I say, not as I do." This worked fine for driving, but it doesn't work for people teaching marketing.
Seth Godin is so incredibly effective because he does the opposite. He literally seems to use his own marketing philosophies in all of his non teaching ventures, which in itself is, using his favorite word, 'remarkable.' He blogged about the original marketing of 'Purple Cow' (a must read biz book), and how he marketed it when it first came out. Everything he preaches today he utilized back then: making marketing as permission based as possible, getting product into hands of a few people who want to talk about it, not being afraid to start small (he self-published the first 10,000).
Brilliant. I wonder if the paperback copies of Purple Cow will ever be considered a collectors item. My favorite part, of course, is his call to action at the end. He wants you to find an audience that wants to listen (and I truly believe that, in most cases, college kids are willing to) and create something we want to talk about (maximize its social capital...if it doesn't help advance my reputation, my chances of finding a girlfriend, etc...what's the point?), and make it easy for us to do so (make it convenient...4 step email sharing processes or not validating parking makes my life too difficult).