A favorite question here at OB is: who are the real experts? 

Most people think of grammar as an area where expertise is especially respected and organized; experts coordinate to decide the right answers and then tell the rest of us what to think.  That is certainly the impression most English teachers give us.  But in fact the "expert" grammar they most often teach was determined mainly by popularity among English teachers, not by what is most expert according to actual grammar experts.

Geoffrey Pullum says the classic Elements of Style is grammatically incompetent:

April 16 is the 50th anniversary of the publication of a little book that is loved and admired throughout American academe. …  The Elements of Style does not deserve the enormous esteem in which it is held by American college graduates. Its advice ranges from limp platitudes to inconsistent nonsense. Its enormous influence has not improved American students' grasp of English grammar; it has significantly degraded it. …

Both authors were grammatical incompetents. Strunk had very little analytical understanding of syntax, White even less. Certainly White was a fine writer, but he was not qualified as a grammarian. Despite the post-1957 explosion of theoretical linguistics, Elements settled in as the primary vehicle through which grammar was taught to college students and presented to the general public, and the subject was stuck in the doldrums for the rest of the 20th century.

Notice what I am objecting to is not the style advice in Elements, which might best be described the way The Hitchhiker's Guide to the Galaxy describes Earth: mostly harmless. Some of the recommendations are vapid, like "Be clear" (how could one disagree?). Some are tautologous, like "Do not explain too much." …

But despite the "Style" in the title, much in the book relates to grammar, and the advice on that topic does real damage. It is atrocious. Since today it provides just about all of the grammar instruction most Americans ever get, that is something of a tragedy. …

The grammatical advice proffered in Elements is so misplaced and inaccurate that counterexamples often show up in the authors' own prose on the very same page. … White not only added the anti-"which" rule to the book but also revised away the counterexamples that were present in his old professor's original text!

It's sad. Several generations of college students learned their grammar from the uninformed bossiness of Strunk and White, and the result is a nation of educated people who know they feel vaguely anxious and insecure whenever they write "however" or "than me" or "was" or "which," but can't tell you why. …

English syntax is a deep and interesting subject. It is much too important to be reduced to a bunch of trivial don't-do-this prescriptions by a pair of idiosyncratic bumblers who can't even tell when they've broken their own misbegotten rules.