Jennifer Crusie posted about some potential issues with author blogging, and on the author/reader relationship.
I've talked about this before, but, first I like and enjoy blogs (particularly author and book blogs) but I think it makes no sense if it isn't something that works for you.
As a reader, I have discovered new authors first through their blogs. I have also, through blogs and the internet at large, learned about various forms of bad author behavior. As of now, there are quite a few authors for whom I went from blog reader to book reader. So far, I have not stopped reading anyone solely on the basis of their internet behavior. (Unless you count plagiarism, but I don't count that as internet behavior, that's general bad behavior.)
Let's face it, there's a lot of an author in any story, so reading books you do feel a certain closeness with the author. Blogging can enhance that, as can other internetty gathering places. But, I think it ends up being like a lot of stuff. Sure it can be upsetting to learn that an actor or an author is not quite the person you built up in your head, should things go badly. But, I can disagree with something a person did and still think they write, act or sing beautifully. If they were on the bubble for me anyway, I may take my time getting to the bookstore. But, so far, my stopping reading choices have been made by the books, not by the people behind them*.
*Except for plaigiarism, but I still think that's a book issue at heart, even though it is perpetrated by a person.