Some things are just not interwebz material.
People may debate excerpts on ze blog. I'll reiterate here what I said in yesterday's comments: excerpts are usually part of a sales strategy. This assumes the book is for SALE (or orderable), whether via traditional or self publishing. If it's not pushing people to buy (NOW) or preorder, your excerpt is wasted. In my opinion and many others'.
But barring your copyrighted content, anything is blog fodder! Blog your LIFE! Your PASSIONS!! Right?!?!
YES. Well, no. Almost.
Just because you're blogging about "your life/passions" doesn't mean you don't have to filter. Someone likened blogging to "reality TV" and "car crashes" in the comments, because it's raw and emotional and you can't look away. Eh...not really.
"Feelings" don't belong on your blog. OK, half of them do. The "YAY This awesome thing!!" or "How cool is this?!" feelings are great for blogging. But the feelings that I most associate with car crashes and Reality TV (regret, sadness, anger, etc.) should never make their way onto the internet--anywhere.
Back to the brand. While no one is happy/professional all the time, your blog/Twitter/Facebook should read like you are. Moments when you're down are moments when you need your friends around you, yes. You just need to TAWLK. But your Twitter followers and blog readers are not your friends (barring the ones that were friends first). They're your Twitter followers and your blog readers.
You love them, but it's, like, meta-love. It's binary code love. Not suitable for heavy emotional stuff--too much is lost in translation. Just think about all those text messages that have come across wrong at one time or another. Do you really want that happening on an interwebz scale?? No.