OK, here's another grammar clunker ... when do you use it's and when is it just its?
Simple rule - NEVER put an apostrophe in ITS when it's used to indicate a possession. For example, this blog likes its short stories. But you ALWAYS put the apostrophe in when it's being used as a short form of IT IS. It's clear this blog likes its short stories.
And a nice segue (oh beautiful beautiful word) to my new find, The "Blog" of "Unnecessary" Quotation Marks. "Loving" this example in particular...