jk... you can't as of now. but i created this thread because an item should be created that lets you do this (call it a Bulletin Board or Guest Book, it can be a crown store item or whatever). Let me know if you agree
I don't think this item would cause any problems since home owners can control their guests' permissions, and since the only people that can enter your home must be on your friends list or one of your guild rosters. That doesn't leave too much room for abuse. And it should say who the message is from automatically. It can resemble the little book at the undaunted site, only with a custom message. I just figured it would be a good item that a lot of people would want, and it will help people visit other people's houses more often (and their own). Every time i visit a friends house i wish i could leave something letting them know i was there