I haven't read this either, but I'm dropping a star because it doesn't have a spider on the cover. Plus, the cover's yellow, which isn't nearly as cool as black.
UPDATE - having now read the book, further comments follow...
David Thorne is probably most famous for his series of real-life letters where he attempted to pay for a utility bill by offering a picture of a spider he drew. Much of his best subsequent material is in a similar vein - based in reality, documenting correspondence between David and some hapless victim.
As pointed out by other reviewers a lot of the book is indeed familiar to people who zealously follow David Thorne's site, but there is still a good proportion of new material that I don't believe has been on the website. There are also some surreal, Monty-Pythonesque jokes... a book-mark on the first page, a table of contents that includes absolute zero (-273) and the Fibonacci sequence, and a centrefold in the middle of the book.
The book is genuinely laugh-out-loud funny in many parts, has some surprising pathos on other parts. It's also an uncomfortable book, as David's humour is mischievous and works best when he has dupes or victims.
If you're a follower of David Thorne, the book, even with the recycled material, is worth getting. If you're not familiar with David's work you may want to search for him on line and check out his website, and I'd guess you would become a convert.