Very light reading, which may be worth getting if you find it very cheap. No surprises there.
What I'd add is that this book seems to me like an interesting example of doing creative work while imposing some artificial limits on yourself. What I mean by this is, the authors could have taken their premise--making fun of some bad examples of writing--in many directions, but they chose to follow a specific form: a quote from Wikipedia, followed by a short and hopefully clever remark. There is a certain restriction in this, kind of like when writing a haiku you have to follow certain restrictions; although, of course, this book's form is not as restrictive as haiku rules.
That aspect made me curious and was one of the reasons why I ended up getting this book. I wasn't expecting a masterpiece but I thought, if I could find interesting ideas on how to approach simple humor, that would be enough. I found some of that, so no complaints.