I attended a panel at CONduit (mostly, I didn't actually go to the panels -- that wasn't what I was there for, but I went to one or two) on self-promotion. It featured such fine writers as Larry Correia and Michaelbrent Collings and was excellent. Among other things, I've learned that I really need to know karate.
Several panel members encouraged the use of social media in self-promtion, but they left out an important point that I'd like to make... you know, for both of you that are reading this blog. Whatever social media you use--Facebook, Twitter, Blogger, whatever--don't just click through when you sign up, read your terms and conditions.
In particular, read the intellectual property provisions and take them into account in the nature of what you post. You don't want to give Mark Zuckerberg a license to things that you write just because you post a teaser chapter. Much less do you want Mark Zuckerberg to own pieces of your book.