The forum has much more emoticons defined than the site. You could use the icons of the forum on the site, but it is not easy because you have to embed them in HTML code.
Only few exist currently on the site, but I can easily add more if you request a particular one
Existing icons can be seen in ben68's profile: http://www.imcdb.org/profile.php?id=ben68
I should add that list somewhere near the comments post area.