If you have a chat system that deletes its history regularly, and if you want to maintain some long-term memory that outlasts the history purge, and if you don't have blogs or wiki or any other sort of public place to put things;
then you put together a regularly posted document and resend it at intervals, perhaps in FAQ format, so that people on the channel see it repeatedly even if they are new to it.
source: Usenet News, from before most nodes were also on the Internet.
