The language changes constantly, and thank God for that. As northern scamp nickyboy says, change is what tells you something's alive. Nevertheless, at any given time, there are right ways of doing things and wrong. At best, using your when you mean you're puts ambiguity between you and your reader, which is unhelpful. At worst, wrong compounding wrong delivers no message clearly and more often than not is just plain fugly toboot. The fact that 'fugly' would not have appeared in any dictionary from the '70s doesn't make it wrong, or a non word, or a bad word. But such innovations should, like the rest of the language, be introduced with care and consideration, and subject to the overriding principle that we are all beneficiaries of thousands of years of work by countless millions of people. We are the inheritors of a language of uncommon beauty, agility and precision, and it behoves us to treat that legacy with respect, even reverence.
Innit.