I once wrote a proof of concept that uses the file system to do this. Basically, writers write their message as a file to a directory that readers watch via inotify. When done in a RAM based file system like tmpfs, you need not even touch the disk. There are security and permission snags that I hadn't thought of and it may be difficult if not totally infeasible to work in production, but yeah... the file system is pretty much the traditional one-to-many communication channel.
