Emoticons or Emotes are faces and symbols that can show how Penguins feel. They usually appear in speech bubbles accessed by clicking on the "Emote Menu" or by pressing "E", followed by various keys what are usually the first letter of the noun.
The "Skull emotion" was removed, along with the heart emote  - however, due to popular demand, the heart emote came back a month later. According to Club Penguin: "There are plenty of other ways to show you don't like something besides using the skull." One of them could be the tongue emote. There is also a special sun emote which can be found by pressing E and D together.
There is also a special tooting emote which can also be found by pressing E and T.
Emoticon and Action Shortcuts
All of the emoticons (excluding party emoticons) were designed by Rsnail.
There are some fan made emotes made using the keyboard.
On November 30, 2007, the Skull emote was removed because penguins were using the skull in a bad way, like threatening of murder or reference to death. The Skull can now only be seen on the Ignore list button.
The Heart emote was also removed as well, however, it returned a month later.
Another emote, the Laughing Emote (or the Smile Emote) was revamped on October 12, 2007, as the old one looked very similar to another emote on another website.