I'm reading a delightful and funny book called Eats, Shoots & Leaves. I cringe when I see it's or its used incorrectly and even some of my most literate and creative acquaintances don't seem to know the difference. This is true even for some of my web friends.

The odd this is this: I've read (and heard) so many instances of incorrect grammar and punctuation throughout my long life that on occasion, I find myself doing it, too. Horrors!

Yes, I persist in trying to explain. Its is used as you would use his, hers and yours. No apostrophe. It's is used when you could also have said It is. Now, is that so difficult? Apparently, it is.