I use Discord since almost one year and I have to tell this is great software (for free) with fantastic GUI and options.
Is much better than Skype and Facebook (is different style of coarse) and slowly I move from Skype to Discord.
How to join:
1.Here is link to download Discord:
https://discordapp.com/download
2. After installation and setup your account use button to join our server (you can see also I am member of other server for Diablo 3 game players):
- Join02.png (35.03 KiB) Viewed 33049 times
https://discord.gg/gZvPNPJ
4. Welcome!
There is also Voice Channel, very easy to start or join.