What is even mote interesting is how this reflects on the chipping away of search engine usage.
Since I run an ecommerce site, what I am most interested is what the "buyers" use. From what I understand, conversion rates from people using google or shopping listings / shopping engines is still WAY above anything that is derived from facebook or twitter, UNLESS their is already an established fan base that is just waiting for either a new product or limited time sale or some such thing.
I would imagine that if you are comparing apples to apples (say, conversion rates for google adwords to facebook ads), then the conversion rate is probably still incredibly lopsided in favor of google adwords. Would love to see any data on this, though.
So in short, I think that social media is great for brand management, and for advertising. Hence, it is beneficial to have someone with a strong marketing background working in social media.
Traditional SEO needs someone with the technical background and know how.
Ideally, in terms of employability, one would have both a strong background in marketing and in traditional SEO.