Story story
Focus on exploration and community, with all that other stuff you'd probably want to do, too.
Cooperative economy: crafting, farming, selling, buying, services
Neighborhoods: suburbs, urban housing, farms, guilds/groups
It isn't necessary to play like part of the community - you can do everything in the game without other players, but it might cost you a little more, or be a bit more difficult.
There will be a type of bulletin board system in-game that is available to all players, and will allow players to advertise their goods/services, or post requests for help or groups.
Space colonization: New colonies are popping up, and as they appear you can be a part of their development.
The main planet is well established, and there is less opportunity for player influence. However, this means that the infrastructure is already in place, and you do not need to be a part of creating it.
On a colony, players can establish cities, spaceports, etc.