Getting back on topic...
I like your revised idea, Mustang. Forwarding messages would be good.
And I agree with Kendrick - RS got boring for me because it was all about killing monsters, getting better armor, and gaining XP. Early on it was fun when all my friends used to hang out in the chat room, and we\'d do stuff together, but then they drifted away, and the overall attitude of the game became \"everyone for himself\".
There was a game I used to play where they had several different types of in-game communication: there were chat channels (channels where you could talk to other people who were playing), in-game chat (the usual \"talking to the person next to you\") private messaging, e-msging, group msging (just talking within a \"group\") and guild chat. Private msging is a definite must, and e-msging or letters would be really cool also. Guild chat would be very useful - that way, guild members could communicate during a brawl.
I also know squat about programming, but I think putting up text on random surfaces, of random text strings, would take up a goodly amount of server space and be a pain to put in. I believe someone suggested having books in RS, and Andrew (the creator) said it would be too difficult and space-hogging to do. I could be wrong, though.