The point of much of the book is that rules, including grammatical ones, are meant to be guidelines.  They aren't engraved in stone, and often need to be broken so that someone can make their point.

A point needs to be made about the whole "blog as book" idea.  One of the things that has always worried me about blogs turning into books is how the use of hyperlinks would be handled.  Footnotes are one obvious solution, but constantly looking down at the bottom of the page to check what the footnote is about can get tedious, especially when there are a lot of notes.  Liberman and Pullum avoid this by using light gray lettering (rather than black) for links, and placing the corresponding URLs in the outside margin of the page, next to the referral.  This makes checking the link content a lot easier, and if it's not a standard procedure for blogs-turned-books, it should be.

Far From the Madding Gerund is a fun book, and an interesting look into linguistics.  The study of language doesn't have to be boring - it can even be fun.