The Book Design blog had a recent post about author blogs, and I really disagree with a lot of what they asserted, at least with YA authors. Maybe it's different for nonfiction writers.
"Author blogs and web sites are not so much for an author’s current readers but serve as a strategy for attracting new readers."
I don't know, maybe this is the authors' hope (not too sure about even that, though), but from what I have seen, it is the authors' fans who read their blogs. I do read Meg Cabot's blog even though I don't read her books, but otherwise, I don't read the blogs of any authors I haven't read. I read blogs for a myriad of reasons, from waiting breathlessly for news of upcoming books to getting insight on their writing process to enjoying the random and interesting comments.
"Most people are never very interested in blogs that are too personal. No one really cares about what you had for dinner last night or seeing photos of your cat. Blogs are not for writing about your interesting life."
Again, I really disagree. I find the personal stuff very interesting. I love hearing about Meg Cabot's ailments and favorite movies and love for cupcakes. I like to read about Sarah Dessen's new baby. The incestuous world of NYC YA authors fascinates me (Oh, Scott Westerfeld, Justine Larbalestier, and Maureen Johnson had dinner with Libba Bray? Fascinating!). All this lets me feel like I "know" them better. It personalizes them and makes me care about the success of their writing. Plus, these people are writers! They have clever turns-of-phrase and jokes and such that are entertaining.
Oh, and I am VERY interested in seeing pictures of authors' cats! Indeed, if any YA authors read this, post pictures of your cats! (I'll accept other animals as well, but they will not be as adorable to me as cats.) Maybe I should start a blog just posting pictures of YA author pets...