[DarkHoodness]

EDIT: Unofficial guidelines that people seem to agree with - They aren't entirely set in stone but please bear them in mind. Happy Minecrafting!

• Don't steal things from other people's chests
• Fill in your creeper holes near inhabited areas (if you're far away and not near other people's creations it's not important)
• Don't leave floating trees/remove big trees entirely
• Respect other people's creations
• If you have to go AFK for a while, please log off the server so that the rest of us can sleep when it gets to night.
• Before you build, take a good look around and notice where the location of other people's houses and creations are, especially if you plan to build something insanely large or obstructing (for example don't block the line-of-sight between the OWI logo and the main base). Check with your neighbours first. A good place to build your own house/base is on the outskirts of the inhabited area, not too close to people's creations, where it doesn't look like anyone has built yet.

Notes:

• Everyone normally carries a bed with them (or at least I do). If everyone says they're in a bed at night, and you can't get to a bed, log out for a few seconds, then rejoin.
• Some of the main areas are connected by mine cart (map here I wasn't being serious when I made this, I'm not THAT nerdy :P) as a safe(ish), fast way of getting around. To use, place a mine cart on a slope facing the direction of travel, ride in a cart, then press the button next to the slope to launch. You can hit the mine cart with a tool while sitting in it to pick it up quickly, or stop between stations.
• Stuff in the community chests in the base is for everyone - Just don't take everything, rely on using your own stuff when you can, and be sure to make your own contributions from time to time.
• Same applies to the food in the Old Mill.
• The apartments were built by Oldnile (Dripik) to house newcomers. When you first join, feel free to pick an un-inhabited room to use until you build your own base.
• It's best to not wander around inhabited areas at night unless you really have to, then you won't be ambushed by creepers and leave holes everywhere.
• If you do remove trees near inhabited areas for wood, replant saplings.