I’ve got a friend whose home cordless phone (yes, she still has one of those) announces, out loud, who’s calling. It’s kind of cool, because if you’re making dinner or watching TV or something, you know whether it’s worth answering. “Call from Vantage Insurance,” it’ll say — a telemarketer — and she ignores it. “Call from David Pogue,” and, of course, she leaps to answer.Turns out the iPhone can do that too. But not one person in a thousand knows.