Stephen Fry's blog of last week (here) raised some points that needed to be raised, and raised them in his necessarily extensible, and indeed extended verbiage.
Long, and rightly so, in his criticism of the pedants - that I like to call Grammar Nazis, who believe that there is such a thing as "correct English".
I believe there is such a thing as comprehensible English. I encounter it all the time. Truly incomprehensible English is a very rare thing indeed, and usually requires a special skill, not to interpret it, but to create it.
Ibelieve there is such a thing as correct grammar, too. It is any grammar that correctly describes a given figure of speech.
Following the rules of grammar is rather like following the contours on an ordnance survey map, instead of following the roads. The contours are there to describe the landscape, not to keep it from floating away. Shall I nail it down? I shall though. Following the rules of grammar is not correct, nor is it safe, helpful, or likely to result in clarity, or even comprehensibility. The rules of grammar are there to help people to talk about language, possibly to help them understand their own language, and certainly to help people to make sense of a foreign language.
Grammarians are there to invent the language that describes language. Grammar is there to describe language.
I do not, and neither do, nor should, you, follow the rules of grammar. We lead them.