When you're too fucking goddamn lazy to put an apostrophe in the word "I'm." Don't expect people who use them to be on phone, since they most likely will have autocorrect, since phones are fucking retarded nowadays. They are mostly on computer, since computer doesn't have autocorrect.
Mike: "im going to the store."
Jimm: "*I'm."
Mike: "i know, 'im.'"
Jimm: "Fucking stupid idiot."