We've setup a discord server for all of opticraft to use. Discord is a Voice & Text application which works in your browser, desktop, mac, android or iphone!
Come join us on it. Follow this link, or hit the connect button on the widget on the front page. http://www.opticraft.net/discord
Discord will likely replace our IRC and mumble servers if it proves popular and useful enough. Discord has both desktop, web, android and IOS apps, so you can stay connected wherever you are.
We have setup an IRC<--->Discord bridge. This means that messages sent ingame and IRC for the respective servers end up in the respective discord channels. This can make discord a little chatty, so you might want to mute the #survival and #creative text channels.
Please do come drop by.