The Nitpicky English Major's Guide to Grammar: there, they're, their

This one really gets to me.  It hurts my grammar snob eyes.  I try to be open-minded in most things, and I know a lot of people just can't keep track of rules for word usage in the same way that I can't keep track of the order of operations in mathematics (but I still remember PEMDAS!), but I get a little bothered when otherwise intelligent people write "there" to mean that something belongs to them.

Here are the simple rules for there, their, and they're:

Use "there" to indicate a position or place or in forming "there are" or "there is" phrases.

I parked the car over there.
There are many ways to park a car.

Use "their" to indicated that a plural noun possesses something.  This noun, more often than not, will be they.

They lost their way.
My mom and dad like their house.

Use "they're" when you could use "they are" instead.

They're going to the fair.
When do you think they're going to arrive?


You could even occasionally have all three words in one sentence, like this:

I think they're going to lose their way getting there.


I know that homonyms (words that sound the same but have different meanings) can get terribly confusing, but you can think of it this way: "there" has the word "here" in it, "they're" has "they" and part of "are" in it, and "their" is used the rest of the time.  Does that help?

Sometimes I think I'm a bit more snobby than I'd like to be by going about grammar like this, and I understand that a lot of people just don't care.  But isn't posting a little series about grammar rules better than leaving pointed comments on people's blogs?  I haven't decided yet.  It's not as effective in reaching people, sure, but it does pretty much take care of my irritation with all the misused words I find on the internet. 
By the way, our internet connection will be turned off tomorrow afternoon, so I'm not sure if I'll get posts up or be able to read and comment on your blog.  My time in the writing lab will be spent tutoring and working on my French class.  I've got a post or two scheduled, but if you don't hear from me, I'm probably still alive, just disconnected.  Have a lovely week!