The service will only allow users to call other EarthLink customers, but the company says it expects to offer a paid service similar to SkypeOut within the next year.

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If the call is missed, it's routed into a voice mail system that users can check on the Web, or via their phone.

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Last week when Facebook updated its Facebook Messenger app for the iPhone it included free voice calling in the U.S. A users can place a call to contacts from the conversation list if that person has Messenger for iOS meaning both parties need to be using the Messenger app.

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