Reading the words of Stephen Fry is great, hearing him speak them is better. Combine the two and add some awesome typesetting by Australian student Matt Rogers and what you get is amazing.
Stephen does have a point, of course. Language is situational, you use different words in a work meeting than you would at home. When you write a paper for an English class, your usage needs to be different than when you write an email to a buddy.
But, it is still important to understand “proper” usage. That doesn’t mean you have to use it all the time, just be aware that there is a standard way of doing things.
Not being aware of the “rules” is ignorance. Knowing the “rules,” when to use them and when to break convention – that is something entirely different.