Facebook has enhanced the iOS version of its Messenger application to enable users in the USA to speak to each other without paying call charges. The VoIP feature was originally launched in Canada earlier this month.
Users can make voice calls over WiFi or a mobile data connection but only to other Facebook users with the iPhone app.
As well as making voice calls, Facebook users can also send short voice messages via the app.
Similar features are expected to be added to the Android and BlackBerry versions of the Facebook app in the future.
[More details: theverge.com; BBC News]