Hey Elissa, my personal philosophy about social media is that I've never thought of it primarily as a marketing tool - it's always been a tool for engaging with the kidlit community first. That's still true now that I'm published, although we'll see if/how it changes as my pub date approaches. Sometimes that means indulging my own small-scale creative whims (Twitter empire, vlog clips, impromptu collaborative stories written via Facebook updates), sometimes it means spouting off about books that I like (either as part of a focused group effort, which does get more explicitly marketing-oriented, or just to be a fanboy), and sometimes it means just hanging around and seeing all the interesting stuff that other people are doing with their careers. I've tried very hard to keep expectations and demands about my own career low on the totem pole, not because I lack self-interest (I have a VAST SUPPLY of self-interest), but because it's not the way in which I'll function best as a member of this community. Doing that would create psychological barriers in my own mind (and probably the minds of others), reduce my ability to be a good colleague, and blunt the pleasure I take in positive things that happen to others.
My online presence has been really good for me in terms of putting me in opportunity's way, if that makes sense. Professional opportunities of all kinds are floating around out there in the ether, and I think I've been able to swim out there into the same big cloud of ether by establishing a social media presence that's an authentic representation of myself, a free-spirited channel for creative expression, and a way to genuinely express my appreciation for all the things I love about the kidlit industry.