As it is a general breach of netiquette to advertise competing items/programs/services publicly on free services such as a MUD, Turf will not allow general advertisement of other muds, talkers or instant-messengers in public places, this includes: channels (e.g. chat), titles, descriptions and other things in that vein (except homeroom descriptions).
It is, however, acceptable for players to discuss other muds, talkers or instant-messengers over private channels.
There is a fine line between discussion and advertisement which is left to the discretion of the Immortals. As in all cases, decisions of Immortals, while not above question, are above argument, and the decisions of Gods are final.