I've found the factoids in Ubotu useful as a sort of a real-time FAQ. It is a bit problematic though when eg on #u-fi you cannot be certain that the other person is talking English which will be the language that the factoid has been recorded in. So I thought that it might be useful if the bot could (if it can't already) store multiple answers for the same factoid and choose the one in the right official language for the specific channel. This way the bot would follow the same principle as everyone else on the channels: conversations in other languages should be taken to language-specific channels. The factoid thing could give out a link to a short guide in the particular language if it bumps into a missing keyword. Also a similar syntax to the package information tool (!info package release) could in my opinion be used with factoids too (!factoid language).
The actual question part of this messages is do you consider this doable or if it already exists, should it be documented better so us users know how to use it appropriately?
You could just create a channel specific factoid like:
!factoid-#ubuntu-fi is <reply> ....
Then when !factoid is called in #ubuntu-fi the factoid for that channel is used.