I'm thinking that's either an older post which hasn't been updated recently, or the SEL team are missing the boat.
While most of it is SEO101 foundational knowledge, the bit on Social +1 is way outta whack. Social mentions (mostly Facebook shares, though also likes/fans/follows/retweets/+1's) are now about 20% of the search algorithm. That fact alone puts them as a +3 and is reason enough for people to get a move on with a social presence.
Even if companies don't have time and resources to keep every network going like wildfire, there's no reasons NOT to spend a few minutes each day to check, engage, make a post, and definitely share blog posts and other news via social channels (with a backlink of course).
That said, companies also should try to keep their social chatter 80:20... 80% of posts should be valuable, resourceful, entertaining and otherwise reader-beneficial, with 20% of posts being blatant self-serving messages (IMHO).
Thanks for sharing. It's worth looking into. Great summary of all white hat and black hat SEO techniques available out there. Did not know there is so many of them, but it's always good to know all of them, just in case