"The English language is constantly evolving"
Specifically, when used to excuse bad grammar and poor spelling. Yes, we're constantly coming up with neologisms and new ways of expressing concepts. Yes, we use drastically different sentence structure than we did a century ago. Writing "your" instead of "you're", "loose" instead of "lose", "it's" instead of "its" (or vice versa) etc. isn't evidence of the language evolving, it's evidence of a lack of understanding of the basics.
(Vice Admiral Sir Charles Cockbrush KCB MBE DSO, who is finding it increasingly difficult to log into b3ta.com wants to duck your aunt and kick your puppy, Fri 9 Apr 2010, 9:18, 3 replies)

I heartily agree with this message

( rofl harris, Fri 9 Apr 2010, 9:47, closed)

ditto.

( Legionary - My god, Brian, there's a message in my alphabets, Fri 9 Apr 2010, 14:27, closed)

or maybe
it demonstrates a fluency and comfortableness with the written language which allows one to translate verbalised thought to text without stopping to think about every little word.

I suspect the frequency of these usages is roughly U shaped in its distribution in relation to literacy.
( Sextant goes to him is emotionally erect, on this day, Fri 9 Apr 2010, 15:28, closed)