There used to be many more smileys than there are now. After a few complaints about how obtrusive they were I instead offered a cut-down set of smileys. What you're probably seeing is references to ones that are no longer there.
It's actually something on the list of things to sort out - A better way of doing it is to offer more than one user-selectable smiley set. That way you can pick your own set, either with just a few smileys, the current set, or the full set.