Playing this game at the moment and loving it!
It's an MMO developed by an indie company with amazing communication.
This game is COMPLETELY player based, there are no NPC towns, instead you have tribes which in some way are like a guild, and you plant your tribe totem and then the area around the totem is your tribe's land. As your tribe's size increases (in terms of how many people are in it) the land your tribe has grows and eventually caps at about 60 people (but you can still invite more peeps to your tribe).
There are then LOTS of different professions used to make your tribe's village, build defenses (walls etc.), build storage tents, build houses and this is all done by players combined efforts and all require different resources which require professions in themselves. There is a skill like system where doing an activity increases that skill, e.g. running, logging, architecture, fishing, strength etc. There is also a thing called "terraforming" which allows players to physically change the world around them. They can pickup grass and there won't be grass there anymore, they can dig a hole and everyone will see the hole, they can make roads in there village, even out terrain etc. which is awesome!
It's pretty much open world PvP but there arent too many griefers (the dev hates griefing) and killing mobs isn't like WoW where you walk out and there's Boar's everywhere, if you want to kill something you have to go and actually hunt it and that takes some time!
But this game is HUGE and AWESOME and is really unique, terraforming is very very cool, I suggest you guys give this a shot.
oh and the graphics beat the hell out of minecraft, the scenery is pretty nice, it's like Darkfall sort of, but better