I used to be a Smiley Hater, but I must say the ones here at tFS have grown on me. I think I would miss them.
I would, however, suggest an informal forum rule against posting only a Smiley and no text in reply to others' posts, however. Normally it is not a problem, but I have seen several occasions where it caused confusion or insult when it needn't have.
Therefore somebody being coy could post:
"

Wouldn't you like to know?"
or somebody irritated could use the

Smiley and then articulate, even in just a few words, what pissed them off.
Some of the ones like

irate:

:grrr:

and

are unlikely to give offence, ever, but still it is more interesting, I think, if the post is a little more substantive than one miniaturized cartoon smiley-face.
$0.02