Following mixed reviews of its social networking addition to iTunes, Apple released figures showing that 1 million signed up to the Ping service following the launch on Sept. 1.

That figure covers a period of less than 48 hours since the launch, so Apple is likely to have to added considerably more Ping users over the weekend. The music recommendation and sharing feature is an optional extra for users who download iTunes 10, and enables them to follow artists and share music-related information with friends.

But for Apple to make a success of its move into social networking, it needs to sign up a decent proportion of the 160 million iTunes account holders to Ping.

"One-third of the people who have downloaded iTunes 10 have joined Ping," said Eddy Cue, Apple's VP of Internet services, in a statement. "As many more people download iTunes 10 in the coming weeks, we expect the Ping community to continue growing."

It remains to be seen if the service - at least in its current form - gets the sort of take-up that will have Apple regularly putting out statements on its latest Ping numbers. In the medium to long term, it is all about trying to move closer to its new rivals' numbers: MySpace has 122 million users and Twitter has more than 100 million. Facebook is way ahead with 500 million users worldwide.