Okay, from what I could gather, the message this article is trying to convey is that training and expertise are an obvious necessity, but without knowledge and experience, it all means diddly squat. A successful designer must also be flexible and not tethered to one specialization.
One particular skill that can be handy is general marketing techniques, maybe not college degree levels of mastery, but enough to fine tune and really nail the message and goal home of the website in question. Beyond that, it just takes years of experience.
Matthew's Obligatory Blog 