I think I may have begun this practice even when I was curating a biblioblog, or it may have been soon after I began blogging here at a personal website, but sometime last year I chose to stop calling blog posts about books "book reviews" for a couple of reasons. First, I don't review books all that often and by review I mean providing an educated judgment of a book's worth and contribution to a field of study. For one, many of the books I read are broadly related to early Christianity or an akin subject, but not a subject with which I can claim to have expertise. A "note" may be similar in many ways, but it is less formal, and it suggests more or less that I had an experience as a reader that I found worth sharing. Second, I have begun writing reviews for journals here and there, and I realized that I had to be far more careful with my words when writing this sort of review than I had to be when I was writer/editor/publisher of a review on my own biblioblog. For some there may be little difference between what is placed on a blog and what is submitted for publication, but I admit I am far more informal when writing for a blog, usually.
For the five or six people that read my personal blog these days I thought it was worth explaining this although you may have already deduced why I changed my language to book "note" a while ago.