A portion of the title of this tid-bit article…you’re and your. They are not interchangeable.
Contractions are one of the basic mantras we learn in grade school yet many writers and bloggers and Facebookers forget the elementary rules. Or perhaps when you’re in a hurry, your grammar suffers.
See #3 under http://dictionary.reference.com/browse/contraction
It’s rather simple. Any time that you use YOU’RE or YOUR, ask thyself, “Is this a contraction or possessive?” When using YOU’RE, try this trick – can you substitute YOU ARE for it? “You’re a great writer!” (You are a great writer), or “YOU’RE awesome!” (You are awesome).
YOUR shows possession and is good for “your bike” or “your Facebook post” or “your pictures.”
I’m sure you’re going to recognize your mistakes from now on.