After a two-week delay, Cupertino,US-based Apple Inc has turned on its iTunes Match software, which attempts to match every song on a person's computer and store the tunes in an online account on distant servers known as the cloud.
The songs can be downloaded or streamed to other Apple devices without needing to physically connect them to the computer.
Songs that are not recognised can be uploaded automatically. The service promises to function with multiple computers used by the same person by eliminating duplicates, Apple said.