I thought I'd post this because UO really went through it all, all the problems, and had some great solutions. This is good stuff for any game that wants to have houses for players. There's solutions in here for anyone, any game style. Housing can keep players, because the more you have into it, the cooler it is, the stronger the desire to keep it is. It's harder to quit a game where you have "ownership" and the greater investment into it.
In the beginning, UO had about 20 different structures that you could build, with variety in sizes (and cost) and styles. This ranged from small one room houses to larger multi-room houses/workshops, to larger still towers, and to keeps and castles. These were non-instanced, and could be placed where ever the ground was flat enough and didn't have obstacles like boulders and trees (there were other obstacles, some quite frustrating, too).
UO started as a totally Sandbox game, and these were some of the functions of houses:
You could set anything down anywhere, stack things on top of eachother, whatever you wanted to do. UO had a lot of difefrent sorts of containors that you could also set down anywhere, stack, and you could store items in them up to weight limits. You could also build or buy furnitures, chairs you could sit in, tables you could put things on, wardrobes and bookcases you could store things in. But anyone could pick things up too, open your containors if they were'nt locked, etc. Some containors came with a key and you could lock them, and if they held enough weight players couldn't pick them up. These were "safe" storage, except that there was a lockpicking skill for thieves.
Your house came with a key, and you could also actually add locks to doors (and get a key for it), or even change the locks (and get new keys). You had to have this key on you and actually "use" it to unlock a door, and then you had to "use" it again to relock the door.
You bought a "Deed" from an NPC, and then you found a fairly flat piece of ground large enough, and then you used the deed and placed by hand a ghostly image of the structure.
Houses each had a house sign, and you could "use" this sign (by double clicking it) and get a pop-up that allowed you to "Name" the house. The house sign also showed the name of the character that owned it. Other players could single click the house sign to see the house name, and who owned it.
Houses were very expensive in the beginning. It took quite a bit of effort just to get a small house, and it took guilds working together to build larger structures, and it was a very long time and a newsworthy item when the first tower was built, and then again when the first castle was built.
To give you an example, the first tower was built by a large group called The Mage Tower. What this was was a community that formed before UO was released, on a very popular web site. It was the message board for everyone who wanted to talk about magery in UO. A board that was at least as active as this board, to give you an example of the numbers of players involved. But that was divided into 3 "shards" that UO started with, and a little more because some players held off starting UO until they added about 5 more shards a week or two later (remember that UO was the first truly massive MMORPG, and there was a lot less people who even knew that such a game could ever be made.)
This is where the problems started showing up:
Players could pick your locks and gain entry to the house and it's containors, and take whatever they wanted. And since there were very slow times, there was a lot of opportunity when no one was around.
They made door locks unpickable.
PKers (UO was wide open PvP) would hide and wait for someone to "unlock" their door, charge them, kill them, and loot not only their house but take their house key too, so they could get in again later unless the player changed the house key on their door. Smart players got in the habit of teleporting to their house without their house key, searching the area to make sure it was safe, then teleport back to the bank and get the key and go back (this really didn't take very long). Unfortunately, not all players are either smart or patient enough.
UO removed the key feature from the doors, and allowed you to simply lock or unlock doors without a key, and they allowed house owners to automatically "unlock" their doors by "using" them, and the doors would remain locked when they were closed. You could set your door to be unlocked by setting it that way.
Other players could still pick up your items, and players couldn't invite others inside unless they really trusted them. Some players would actually infiltrate guilds to get inside their guild houses where there was a lot of stuff stored.
Solution The Lockdown, this is a great feature:
UO added a "lock down" feature, where a player could lock down items where they are in their houses. No one could pick them up until the house owner "unlocked" the item. What was so great about this besides the obvious was that it allowed for players to create museums and show places for the public. UO had items that were very rare, some one of a kind rare, and it also had specially named items from major events. Players could also write books to describe these things, or tell their stories, and lock those down next to the item. Players even made libraries, where they could safely display books of lore or even just player written fiction. Players could make veritable temples to whatever they wanted. And all this was for public display and consumption.
Some few thieves were good enough to sneak right past the owner, into a house unoticed while the owner walked in, and wait until they unlocked things, and then steal those things right in front of the owner, and run. This was done only for valuable, rare type collection stuff, or for uber gear.
UO added a function where a player could search their house "automatically". They could use a skill called "detect Hidden", or access their house sign and click a "search" button. This did a search and told the owner if anyone else was in their house, hidden or not. Some players still had things stolen, just because we get lazy sometimes.
Player vendors at houses. These were NPCs that a player could place in their house, or on the front steps or porch, load them with what they wanted to sell, give it a selling price, and let other players buy off these vendors at anytime. So players could sell their goods even when they weren't there. UO didn't have Auction Houses set up by the game. The only auctions in UO were special player run events. These events were where the best stuff, rare items and uber gear, was usually sold through bids. This was great, "realistic", and something that the game Auction Houses miss out on. This added a special flavor to the game, an all new and different play feature, and was social to boot. But the player owned NPC vendors also added shops owned by players of all sorts, that ofefred what players made as well as loot they wanted to sell. Most players would get to know the owner by chance encounters, and owners were always asking buyers if they could improve their shop, their offerings, how they could be better. because they were in competition with all the other players to sell usually the same stuff. "Location, Location, Location" made some housing spots very valuable, and players even bought and sold these spots just for the investment in them.
"Urban Sprawl": UO's world just wasn't large enough. Eventually, all the spots where a house could be placed had a house on it. The game world just wasn't built for it, and everywhere players went there was houses. The seemed to be few wild places left, and those that were there just weren't very large (and even so, still usually had a small house or two there).
Now, in one sense there was a benefit to this. Houses were used as hubs for these areas. Players could resupply themselves with spell reagents or bandages to continue hunting the area. But mostly, it was just a negative, as the entire world seemed stuffed with houses.
A huge world, and properly engineered to keep wild areas wild is what's required if a game wants to go this route.
A key problem with such a world is the numbers of items. It's not so much one house, buth when a player runs into an area full of house and his computer is trying to load up thousands of items, there's gonna be lag problems. UO had a range on these items, like all games. But it was too condensed, too much, even in a small area.
UO made it so that the player didn't start loading all the items in a house until they actually entered it. They did it in such a way that worked very well. You might get a very brief pause, but that was it for most players.
This caused a new problem that they never fixed, at least in my mind. Players like to decorate and make their house "special", and that includes placing items on their porches, steps, and even on the open top floor of their towers and castles. I think that a limited system of viewable items here would be very good. If a game has instanced interiors, like Skyrim for example, that automatically does this...just sayin'.
Customized housing system. This was one of the best thngs I've seen for MMORPGs. Instead of a predesigned house, you placed a foundation. And then you could build it up any way you wanted, within some realistic construction guidelines. In other words, you needed to have something below the second floor for it to be supported by. This could be walls, or it could be support pillars, or projection arches below it.
Basically, UO gave you a wide variety of walls, stone, woods, stucko, and in a variety of flavors. They also had short knee walls. Each wall could be with a window or without. And these all came in short sections. So if you had a foundation that was 50 feet wide, you could pick and choose each 5 foot wide section along that wall. And you could place a variety of door types in place of a wall. And you could add interior walls anywhere along the inside floor plan, or doors. So you could really make it pretty much any way you wanted as far as floor plan.
Even the floors had a lot of options, ans they eventually added carpets.
Then, you could add items, furniture, etc, anywhere you wanted. Players could really decorate this up and it made for some really great places. The libraries, temples, museums, it was all enhanced. Of course, some players have no eye, and really made some monstrosities, heh.
You could leave upper floors open (no floor) for that Great Hall look too.
Well, I think I've pretty much covered it. I know this answers some problems I've seen posted in other threads. I hope this not only gives some answers, but even raises some questions. I think player constructions, including in cities, is a very big part of the future of MMORPGs.