The spawn could be a great advertising place. The server can initially sell the signs to players and then its up to the players to trade them. This would reduce spam in the chat channels. This can also work with outside companies. For example Coca Cola could pay to have an ad somewhere.
I think this is being avoided to reduce the amount of visual spam. Spawn should contain only what is necessary for new users to know, anything more and things would be a little confusing. Here at ECC we like to welcome new users in an organized and non-threatening way. Jamming ads in their faces may really give new users the wrong impression.
