Emotes (Emotion codes) are commands which make your character perform movements such as waving, coughing, dancing or pointing. They're an excellent way to convey a feeling to those around you and much quicker with more impact than typing your message in the chat window. WoW supports well over 150 different built-in emotes that can help players immerse even better into the game world especially on the Role Playing (RP) servers.
To perform an Emote, type in the chat window:
/agree
/plead
/shiver
This will perform the Emote and anyone around you will see you. You can also direct your Emote to an individual by selecting the person and then typing /whistle and you will whistle to that particular person. It will also automatically generate "You whistle to <person's name>."
Emotes is the only way a player can communicate with players of the opposing faction; they can see the emotes that you perform. On the PvP servers, waving to a player of the opposite faction is a good way to indicate that you do not wish to engage in PvP with them.
Making Your Own Emotes
You can also do a personal emote using the /me, /em or /emote commands (they all do the same thing). For example, typing "/me slaps Tyran around with a large trout." will show exactly what you expect it to show on screen: "Xinhuan slaps Tyran around with a large trout."
Using your own emotes will not work for cross-faction communication, someone on the opposing faction would only see "Xinhuan performs some strange actions."