I had a great time at the Western PA SCBWI conference a few weeks ago. I signed up for four different informative sessions with editors and agents. My favorite of the four ended up being the one I was least sure about signing up for beforehand: Social Media for Writers.
The social media session (hosted by the very smart and funny Tricia Lawrence of the Erin Murphy Literary Agency) calmed me down. Ms. Lawrence's advice was to pick social media platforms that are comfortable for you to use and focus on those. Don't worry about being everywhere, because that will only cause you to spread yourself too thin and leave you with no time for the one thing you should be doing—namely writing. You won't drive yourself crazy trying to do everything. You might even have fun.
While a social media presence definitely makes you more visible to potential readers, the truth is that there's very little evidence that a big social media following translates directly into sales. So if social media's not your thing at all, don't worry. If you write good books, readers will find them. You might want to dip your toe into a platform or two for other reasons, though. (See this Twitter for Writers post for a few of them.)
My takeaway from the session? I'm going to keep blogging and tweeting, and I'm not going to worry so much about the other social media platforms. I'll take the time I would have spent on those and use it for getting those words on the page.