Buildig is a cool idea, but it would have to be regulated with deeds and builkding codes from the moderaters, if you didn\'t follow them, your house would be destroyed and you would have a pile of stuff where it was, otherwise, people would build anywhere and mess things up.
Edit: Also, you should make a model of your house and send it to the devs for approval, so nothing to outlandish and unfeasible is built, like inverted houses, or really small houses because the modelers modeled out of scale or something.