Someone left a note for me in my house which I didn't find for days. I knew what I had in that basket. Why would I look in it? So I didn't find the note requesting flax seeds for ages. This was disappointing. (The debacle surrounding the delivery of the flax seeds is another story. It involves getting lost, finally finding his farm, tresspassing and losing 8 hit points to find a basket to the put the seeds in and still not knowing if he every got the delivery which was probably much later than he needed it anyway.)
Another time I also went up to a different neighbour's house and left him a note in a basket in the middle of his road. I didn't know his name so I couldn't pm him and every time I wandered up to his camp he wasn't there. I think we come from different time zones. Three days later the basket I left with the note was still there and there had been no visible effort to reply, so I gave up and retrieved my letter.
Some of us have set up a system of mailboxes where we have an urn just in front of our houses to the left of the door. These are in unclaimed territory so you don't need the "Theft" skill to access them, and we are using these for mailboxes to leave each other notes such as when we are not logged on at the same time.
Rural mail delivery service has begun.