Was talking to an old guildie last night and he introduced me to a new VoIP that is very new age. For those that work in the Computing/Programming side, it's very much like Slack.
The VoIP is
-Free to use (no server costs)
-Unlimited number of people an join
-Consists of "Instant Invites" for temporary guests
-Text channels for free chat anytime
-Browser based, mobile app and program, so access is readily available if you don't want to download
-Servers based in all parts of the world (West US, East US, Singapore, London, Amsterdam, Sydney)
It's great for guilds to use as an alternate VoIP, and a great way to communicate outside of the game.