What is the purpose of a book review? And are book reviewers writing anything useful?

Michelle Kerns has been experiencing something of a book review epiphany (or, as fellow Simpson fans will appreciate, an epipha-tree). After compiling my list of the top 20 most annoying book reviewer clichés she indulged her self by surfing about the Internet in search of fellow book reviewers in thrall to reviewerspeak. The shocker came when she realized at least 95% of the reviews don’t say anything useful at all.