This isn't the definitive article as far as we're concerned, but it's certainly a step towards a future where social networks like Facebook are central to every aspect of our lives; in this case, talking on the dog and bone. This new app from Vonage allows owners of iPhones, iPod Touches, iPads and Android-based handsets to call their Facebook contacts - without knowing their phone number. The only condition is that both parties must have downloaded the Vonage app:

So assuming you're on WiFi or have an unlimited data tariff (not as likely as it use to be), you can make free calls - that's nothing new, of course.

Turning your Facebook account into your phonebook throws up two issues; one concerns traction - take the percentage of Facebook users who have a handset-compatible device, are aware of the app and actually download it - and there probably aren't many Facebook friends you can call.

The second is that if your connections on Facebook were really your friends or even individuals you had the slightest interest in talking to, you'd already have their phone number.

Both are issues are likely to be resolved over time; if not through this app, then there's no doubt this functionality will become native to the official Facebook app, and may become a native feature of handsets - Facebook has the sort of reach amongst consumers that makes it viable. And the continuing erosion of personal boundries will invariably mean that collectively we won't worry if distant strangers have more immediate access to us; for some, collecting friends on Facebook is a game, and throwing away access to the minutaie of our lives will continue to occur without giving the matter a second thought.

Thanks to avid Bitterwallet reader Ben for the tip-off