OK, so this isn’t the first time I’ve seen this. From the Washington Business Journal’s review of Now is Gone:
You have likely also heard of social marketing [sic] and maybe participated in some way through FaceBook, LinkedIn or an industry blog.
Now I admit I’m no expert (and I haven’t even got to reading the book yet), but I believe the reviewer actually means social media.
I’ve seen coworkers make the same mix-up. Mind you, that doesn’t mean that you can’t do social marketing with social media…