Just started about an hour ago, probably won't take long to read, though its rather large there are lots of pictures and it's very easy to read quickly.
I love this so far. Different, unique, and very clever. Plus, its actually funny.
I've never been on Allie Brosh's blog, but I really don't feel its necessary to have been before reading this.
Review to come (probably going to finish it in the next hour or so)!