When you post about a book, put the book title in the tag line so we can easily find posts on a given book.
As I tell my students, be kind to each other. The Internet is full of assholes; don't be one. Disagree, disagree vehemently, but politely.
Fiction is fine, non-fiction is fine. When it's your turn, pick a book that looks interesting and that someone could reasonably read in a month. If you really, seriously, strenuously disagree with a book choice, bring it to my attention (or the community's) but for the most part, my recommendation is gonna be "sit it out for a month, then."