New service helps Twitter followers call each other

US IP telephony company Jajah has released a service that lets Twitter users call each other directly through the micro-blogging service – without charge, and without even knowing each other’s phone numbers.

The feature, currently in beta stage in the US, lets users call anyone who follows them on Twitter, as long as both are signed up to the jajah@call service. It limits calls to two minutes, a length it says is the verbal equivalent of a 140-word tweet. But the company will evaluate that length during the beta period, it says.

Users can call each other by typing “@call@username” into Twitter, keeping their phone numbers private. The tweet, which is expected to work on any Twitter-enabled device from mobile phones to PCs, causes both phones to ring.

The development follows an announcement earlier this week that Vivox, which provides the integrated voice service for Second Life and other virtual worlds, will release a voice chat system for Facebook.