Dave noted the it’s/its confusion in this NewsDay article about the 50th anniversary of Strunk and White’s The Elements of Style:
In 1918, he self-published a writing guide for his students, which they could buy at the campus bookstore. It’s main precept was “omit needless words.”
And needless apostrophes.
Our local supermarket uses the apostrophe on all the signs in the produce dept. “Potatoe’s”, “onion’s” etc. It really bugs me.