Your Help Needed with New Social Media

So, I need some advice.  What social media networks should I be on and how much attention should I give to them?

As we get closer to the launch date of Resisting Gossip, I will want to be connecting more and more with folks who might want to know more about the book.  I want to be wary of the dangers of self promotion, and at the same time do my best to get the word out on the street of the ideas in my book (a difficult balance beam to walk). I know about some of the pitfalls out there online, but I need your help to navigate this better.

I'm already here at Hot Orthodoxy, and present on Facebook and Google+. Where else should I be hanging out?  What things should I avoid?

I've been on LinkedIn for a while, but I've never done much there. Dear readers, what do you recommend that I do there? Make connections? Update my profile? Post information?

I just joined up at GoodReads. Who else is there? How many books should I rate? What is the benefit of hanging out in that neighborhood?

I'm getting close to joining Twitter. Sweet Tweethead friends, what advice would you give a newbie to the Twitterverse?

Where else do you hang out online and what is the benefit of being there for you?