Wow--what a link, Bean! I'm not even through it and already I have a bunch of stuff. First, though, I'd like to say that I personally wouldn't categorize his comments as mean; they strike me as simply announcing practicalities, no frills added. For ex., But isn't one person's mistake another's standard usage?
Often enough, but if your standard usage causes other people to consider you stupid or ignorant, you may want to consider changing it. You have the right to express yourself in any manner you please, but if you wish to communicate effectively, you should use nonstandard English only when you intend to rather than fall into it because you don't know any better.
Well--he's right. You're not likely to be hired for a prestigious PR job if you say 'ain't got no'.

A "wow" moment for me: If you think a common error is missing from my list, check by searching with the "Find" command in your Web browser. A surprising number of people don't know that they can search the text of any Web page with their browsers, but it's a trick worth learning. What the eye misses, the browser may catch. I had no clue about this, so I went to my Help button, and found out this capability is found on the Edit function. And it works!

I found his comments here relevant: Americans have it all wrong, the correct usage is English (Canadian, Australian, etc.).
Read my page called "The President's English."


Lastly--what do you all think about this? The primary job of a dictionary is to track how people actually use language. I thought the primary purpose of a dictionary was to define words.