It's ust a simple Hook for integration of smilies.
Written for the pnforum but might be used everywhere ;)

pn_bbsmile now optionally reads additional smilies from a separate folder. You
can define your own shortcuts and aliases for them as well as an alt text for
the images. These alternate text may start with a _ and will be treated as a
define in this case to make it multilingual.
You can also (de-)activate the additional smilies one by one.
