Hmm. 40 year here who really likes using them. I find over instant messaging, which we use a lot at work, when you are just typing text a lot of the real meaning behind what you are saying is lost.
Compare the following mentioned during a code review:
Your code is crap
Your code is crap :-)
The first is taken seriously, the second is more of a sarcastic joke. The meaning conveyed is even stronger when the picture is a comical and brightly coloured smiley face rather than an ascii smile.
I guess it's cultural, but I wouldn't IM "your code is crap" during a code review with or without an emoticon. If the code really was crap I'd be more constructive. If it wasn't crap I wouldn't say it was. Why wouldn't you just say what you mean?
Compare the following mentioned during a code review:
Your code is crap Your code is crap :-)
The first is taken seriously, the second is more of a sarcastic joke. The meaning conveyed is even stronger when the picture is a comical and brightly coloured smiley face rather than an ascii smile.