You won't need to bother with calling your contact on Viber via Skype, as you will already know what accounts the contact has in your address book, and which contact point they use 99% of the time, so makes Oper8tor defunct.
Who the hell needs to call Viber via your phone or skype anyway?
oh and it is free.
Oh and I can still call via my mobile, landline, facebook, skype, Viber or by any other means, without doubling up on costs by also paying a charge for Voip via Vonex.
Nice.
Lastly, the most important contact is one to which you can text or post too.
Merging of the social apps to enable one stream of content is number one issue today.
Unfortunately you can't do it, as it breaks both facebook and twitter rules and regulations, in which you can not merge social data from their app with another.
Facebook messenger in fact have just come out again with more robust rules to negate this issue.
Good luck.
AWD Price at posting:
0.0¢ Sentiment: Sell Disclosure: Not Held