I think it has something to do with this
thread:
https://permies.com/t/69212/Emoticons-repetitions. I think Paul made smilies disabled by default. If you want them in your post, there's a little check box when you're writing the post that says "disable smilies." (it's down below the "attachments" tab-thingy). Make sure that box is not checked, and it
should work.
It could also be that you're typing in the code a little off. Like, :O doesn't work, but :o should. 8) should get you a smiley with sunglasses. There's one with an afro, as well as one with horns, but I don't remember how to make them..
This is an old screen shot (from here:
https://permies.com/t/49855/Stupid-Simple-Emergency-Solar-Dehydrator#400974) of the different smilies that are hosted by permies, but I don't know what all the little codes to get them to work are, any more
Ah-ha, here's the "cocky smirk" and afro codes: ^-^ O0