On social media...
Social media may be an okay tool for keeping in touch with people you already know in real life, but your screen audience will be passive. Virtual relationships just don't translate into the actual world, in my experience.
Especially when it comes to selling books. My current publisher demanded that I renew my presence on facebook. I've ballyhooed my new novel there beyond all shame. I can't verify that I've sold a single copy as a result.
On the other hand, I will travel some miles to read from my work face to face with real breathing humans. My last book signing sold more books than there were people in attendance, and yielded conversations with some interesting people I want to know better.