Ever needed to communicate to your friends and guildmates but you never could catch them online? For example, I went vacationing in a time zone that was 10 hours time difference. It was difficult keeping people from leaving my guild, and I wanted to let my officers know that I would be back soon.
For this reason, I think that something along the lines of letters would be handy. Ex. Pirate 1 wants to have Pirate 2 meet him at X o'clock. So he sends a letter that Pirate 2 gets when he comes back online from Pirate 1.
Go ahead and post your thoughts.