Somewhere, don't ask me where, I picked up the idea that publishers don't like works that the public has already been able to access. When a family member suggested I post short pieces of fiction to a blog to help myself get motivated, I hesitated because I assumed it would be impossible to publish later; I'd have to write up an entirely new piece if I wanted to publish something in the same genre as the piece I had blogged. (I went ahead with the blog anyway. I wasn't writing anything up to then, so my publishing potential was about equal.)
I thought it might be good to verify my assumption here, and while I was researching in preparation to ask the question, I discovered this blog: How to Blog a Book. It's being published! It mentions several books (one of which I've heard of) that were blogs beforehand and the author says that the techniques she used will work for publishing both non-fiction and fiction.
So now my question is, are there publishers who absolutely won't publish a blog? Do I diminish my chances of publication at all by blogging my work first?