In all honesty, I don't think the site is ready for this yet. Having been on the .org one for sometime it is somewhat hard to police and also difficult to know where to draw the line. There is a fine line between banter and tongue in cheek bullying evident over there, only the smilies tell you otherwise
I agree, there are times when we would like it, but I think it would run away. Never say never, but not at this time chaps and chapesses.
The team have discussed this, we may decide to run a trial version sometime in the future to gauge reaction and to see what gets posted and how or if it offends.
Cheers
Mick