by Rob Sullivan
SEM is a complicated industry with various disciplines. There are firms specializing in different areas of the industry from traditional SEO, to PPC to content development to link building. In fact, it's becoming more and more rare to find a company that does all of these in-house.
And this is why I think SEM is similar to being a doctor or lawyer. Not because we have to go to school for years and years, but because we are always learning. In fact I think I don't believe we do search engine marketing. As with doctors, we practice it.
I say practice because we can never know all there is to know about SEM because it is always changing. Maybe this is why so many in our industry use a phrase near and dear to my heart: It Depends.