A favorite social media site of mine is Goodreads. I enjoy it not as a place to promote my own books and stories, but as a reader. I am a reader on Goodreads. It’s where I track my own reading. My reviews there are basically for my own benefit and rarely include more than a sentence or two. It helps me keep track of what books I have read and what books are still on my TBR pile.
The most valuable place there for me are the book recommendations. Based on my reading habits, I get lists of books that are ‘similar’ to what I enjoy. I’ve been introduced to a number of new authors that way.
I also participate in a few 'book clubs.’ I love chatting about books. The members there don't even know I'm a writer or if they do, I never promote there. It has been my one 'safe' place where I didn't feel I had to promote every second. On Goodreads I'm a reader first, writer second.
I’m not a visual person, so Pinterest pretty much bores me. Facebook is good, but sort of functions for me as a website. Goodreads is the place I feel I can ‘hang out with my peeps.’
I got off Shelfari for that very reason.
Here are a few more links about the acquisition of Goodreads: