Messenger 11 Beta) allow for the saving of chat archives on a server for future retrieval.
Most IRC clients and many IRC bots include chat logging to a local file as a standard feature.
Websites exist that publish chat logs, usually dedicated to a single channel and including a search engine.
Some IRC networks have published guidelines on making chat logs public.
[1] Due to their real time nature, chat logs may be used to identify anonymous users by correlating information posted on different mediums.