“The Idler Wheel” is counting on the devotion of Ms. Apple’s fans. Before she appeared at South by Southwest her manager, Andy Slater, said he told Epic Records: “ ‘I want you to do nothing.’ I said: ‘Don’t make any posters. Don’t make any cards. Don’t put out a single. Just don’t say anything. Let her play the show. It’s been a few years. Let kids go to the show, film the thing, put it on their blogs, and you don’t need to do anything.’ ” Almost immediately after her set amateur video clips were on YouTube..."