Oh, and about Pinterest for writers, as someone asked.
I think if you're a writer trying to build a platform as one must all the social media you have time for is the right idea.
I use Pinterest avidly not to promote my book, just because it's fun. Sometimes I do pin my paintings and collages on there, though. As I have a public figure account and my website is on there some of my website click stats do come from Pinterest. If those dear souls buy a book or read an Internet thing then I am promoting my writing on Pinterest, but by providing good content that gets people curious, not just by endlessly pinning my book cover.
The Internet is a vast rabbit-hole that people love to get lost in. Social media like Pinterest, Instagram, Twitter, and Tumblr, all of which I am active on, are a way to lead people on the rabbit hole back to your website where they can learn more and perhaps buy or read something. Plus you may find you enjoy it. The internet is fun!