[adrianmonk]

Here's how I keep this straight mentally.

The rule is, in English, you can make a noun possessive by adding "'s" to the end.

Let me emphasize one part: that's the rule to make A NOUN possessive. "It" is a pronoun, not a noun! The rule doesn't apply any more than it applies to a verb or an adjective.

Hence you don't have stuff like "you's", "he's", "she's", "we's", or "I's", and you also don't have "it's".

[EpicEng]

Pretty sure we do actually have he's and she's. "He's being an idiot", or "she's wrong about that."

[cjm42]

Those are contractions, not possessives. "He is" and "she is", just like "it's" is always a contraction, never a possessive.

[jstanley]

You're just proving the point: "'s" is only possessive for a noun. Your examples aren't possessives.

[EpicEng]

Yes, I misunderstood his point entirely. On reading my response again I also realize that my examples come off as a not so subtle insult, and which is not what I meant.

[guyzero]

Those are not possessives. They're contractions, like it's.

[buzzy_hacker]

Yes, but as a contraction of "he is", not as a possessive.