Yahoo Messenger, one of the greatest IM clients has a support for emoticons that the people send to express their moods and emotions in a better manner.
Yahoo Messenger has a good list of emoticons consisting of all emotions from happy to sad but it also supports certain other emoticons as well which it did not list in the emoticons menu by default. These are the Hidden Emoticons of Yahoo Messenger.
By default Yahoo has some 60 emoticons (as shown above) and it is not possible to add more to the list but to overcome this thing Yahoo has introduced some other emoticons as well which are not very common and you can actually surprise your friend with that.
To use these emoticons you just need to enter the code in the chat box and surprise your buddy with the new emotion symbol.