The rumour that Mark Zuckerberg, CEO of Facebook is considering a possible move into the digital music business, has popped up online again today, further heating the rivalry between MySpace and the site.

Zuckerberg is talking to song-streaming services and music community sites, such as Rhapsody.com, iMeem.com, iLike.com and Lala.com, about a potential outsourcing deal. The deal would better integrate the music experience of Facebook users. Unlike MySpace, which had a successful launch of MySpace Music on September 25th, the deal would not see Facebook securing licences to distribute music or build a proprietary system from scratch.

If the rumour proves true, then Facebook will not only be catapulted straight at MySpace but also indirectly at the likes of Apple’s iTunes and Amazon.com… an overtly competitive market to compete in by any standard.