Thanks for the feedback. Just thought I'd throw the idea out there and see what came back. Maybe not such a good plan after all.
The problem with Facebook is people tend to have diversified friends. For example, among spiritual people, its common for people to have problems balancing their spiritual side with family and friends who are not. So a lot of us have two accounts, one for family and close freinds, and the other is our spiritual/professional. But even with my professional account, advertising books on it wouldn't go down well, since the majority connect with me for the spiritual side of my life, not because we share an interest in books.
The only time this might work on Facebook, is where an author has an account specifically for friends who are also readers.
Tell you what you could think about for FB. Authors will have Pages for themselves as an author, or for their series or special books. Now if you could cross post to pages rather than accounts, it would work because the target markets are similar, although it would need to be very selective of the genre posted. You'd also have to make sure there was no spamming of pages. My own series page doesn't get many posts, so even 1 post a day into it would be spamming it. There is a wordpress addon which cross-posts a blog entry to FB, so it can be done.
BTW, I've been following your own '3rd book' post with great interest, very inspiring. It's got me motivated to finish my next one. Dying to see how number 5 goes for you.
Thanks. So am I.

All it needs is actually finishing it. But I'm on schedule, so not concerned about that at this point. I'm more interested in where its going at the moment, than how it goes when released.