Keywords can also be used to associate your userpics with the moods you select when making journal entries. For example, if you give a userpic the keyword happy, any time you make an entry and use the happy mood, the userpic with the happy keyword will be used when you view the entry on its comment page using a site scheme. If you view the entry on a customized comment page, or any other journal page (such as Recent Entries, Friends, etc.), your default userpic will be used. In addition, if you select a userpic to use for the entry using a keyword, that userpic will be used and any mood you select for your entry will be ignored when displaying the userpic.
I figured this could go in as the third paragraph of the "Keywords" section.
It would also probably be a good idea to add something to FAQ 32, but that could probably just be a quick sentence and a link to FAQ 95.