As I do once in awhile (neither frequently, nor consistently), I corrected a friend on Facebook on their spelling. Very simple correction, just "you're" instead of "your". And she deletes it. What bothers me isn't that she deleted it, but that she's one of my classmates in my teacher certificate program.
I've seen a handful of my fellow "cert students" (as we call ourselves) make these sort of posts often enough. In fact, there's one guy that I've read that is almost unreadable the way he'll type (everthin is lik short lik this an its hard 2 read cause he typs lik a 5 year old). I corrected one of their essays which had atrocious spelling or improper homophones (different spelling, same sound, different meaning). Every time I read one of their posts, I want to scream, "You're supposed to be a future teacher! A TEACHER! Set a goddamn example, you moron!"
Now, I'm by no means a perfect writer myself. Quotemander and other people who have edited my writing can attest to that. At the very least, though, I know the basics. I'll certainly make mistakes along the way, but to not even know the difference between basic words like "you're" and "your" or "its" and "it's"? How will they be future educators if they don't even know the difference themselves? It'd be like being an algebra teacher and not knowing how to do long division.