I played alot of single player and still have my copy.
How does one join multiplayer?
Magic carpet? Isn't that a bit "broken" for creating/fighting monsters? Same for warping?
What's with all the different world names listed in this thread? What's the differences of each?
If you're curious about our multiple worlds, you start off in Caprica. This is the "main" world for now. Find somewhere undeveloped to establish yourself. Near the Caprica spawn point is an area with several portals. These portals take you to other worlds: Ragnar, Hellworld and Skyworld.
Ragnar is our old map, that contains many old grand works we can't bear to part with, but is out of date content wise (no villages, old mines, strongholds etc) and doesn't get backed up regularly, so building new things there isn't recommended. It's gate is grey stone.
Hellworld is self explanatory. Due to difficulty with our multiworld setup, the nether doesn't work as it normally would.. but in order to still have access to nether content (and resources), there is a nether world map that is accessed through the red gate. Besides Caprica, Hellworld is the only world with monsters and animals.
Skyworld is a world that is above the clouds with floating islands of various sizes. It's beauty belies its danger, however - falling to your death is very likely. It is accessed through the white (snowblock) gate.
Magic carpet and warps don't hamper monsters.. They're mostly for fast travel to distant lands (and boy do we have some distant, distant lands, especially on Ragnar), and for easy scaffolding during building tall things.
Added at: 15:31
Oh, and the server address is 66.135.42.50: 27065 and I'll need to know your username to add you to the whitelist.