OK, I'm going to rant here. Bear with me.
"your" is a possessive. It's used in front of something you own. Like "your house" or "your child."
It is NOT used in the case where you would otherwise use "you are," such as "your hot" or "your going." In this case, what you want, really, is "YOU ARE," which is shortened to "you're." So "you're hot" or "You're going to Canada" or whatever.
Of course, nothing is worse than "ur."
And then there's "there," which is even worse. "There" is used to define a place. "We're there." "Their" is a possessive, as in "their coats," "their house," etc. But wait! Then there's "they're!" Guess what, that's just like "you're." It's short for "they are," meaning "they're hot," or "they're going to Canada." Luckily, noone's figured out a way to slaughter that in internet speak.
Sometimes I wander over the internet and wonder how half the people on it graduated from high school. I'm the first to admit that I'm a bit of an English snob, and that I'm more picky than most people. But I see basic grammatical, spelling, word, and punctuation misuse in 90% of posts, bulletins, comments, etc. This is your native language, people! I work every day with people from other countries who speak better English than a lot of people on LC.
I s'pose, in the end, it's a pretty huge indictment of our educational system and the erosion of our native language caused by the sloppiness encouraged on the internet.
Seriously, that's supposed to be a JOKE!
On the other hand, I'm immensely in favor of the internet for a myriad of reasons, including the fact that it encourages people who might not otherwise communicate in written form to do so. Because it encourages the exchange of free ideas, of communicating across distance and culture, of finding friends from all walks of life.
That said, in the end, I just wish they all knew the @#$%&% difference between "your" and "you're." That would really help me get through the day in a much better frame of mind. It's the little things that count, after all. :)
... grr, and don't get me started on the incredible overuse of the elipses as a punctuation tool.
End rant.