I think Pirate101 should have a PM based thing ingame. The message in a bottle. Basically, you buy a bottle from the housing vendor in Skull Island. With the bottle you can write a message and send it to any of your offline friends. The message would go directly to their house. The pirate the message is sent to gets to keep the bottle. If the bottle is not read in 48 hours it dissapears. Pirates would get an option to disable getting bottles in their options. Bottles at most should cost 50 gold. Messages would be filtered, of course.