Two weeks ago Wal-Mart made the decision to shut down its DRM services for the old music service they one supported. At first, Wal-Mart told everyone they had until October 9th to backup their purchased music or it would be gone forever (unless played on the same PC).
Early adopters protested, and as a result Wal-Mart decided to extend the server shut-down deadline. Although, Wal-Mart hasn't given a date yet but only made the comment of "they will maintain and operate these servers for the foreseeable future."