Beginning
This literally began as a meme in <You>, allowing people to express their feelings through emojis, emoticons and various of pictures instead of having to type it out. The emoticons expanded and eventually there were around 40 of them still increasing daily. I'm now expanding the addon outwards to those who want to use it, feel free to add more emoticons, but remember it's client-sided, so everyone has to have to same version as you. I'll be updating this, so feel free to post on the ToD thread (Theatre of Dreams) in case there are more emoticons you would like added.
Install
To install put the folder into your addons folder like you would any other addon.
Use Emoticons ingame
To use emoticons in game, you must put the emoticon inside two colons. The emoticons are written below, but an example is :100: which would show: 
ingame. There are only few exceptions that doesn't use colon, but these are likely to be removed and changed to colons only.
These function in *any* chat, but they can be disabled in the options menu. You can also send mails with emoticons in them. You can potentially have an unlimited amount of emoticons, filling as much as a normal message box would fill.
If you run a default chat addon, you are able to right click your chat bar to see 10 random (almost random) emoticons, which you can click to instantly have them typed in your chat.
Eye Candy is a mode that allows you to see the emoticon before you send it. Meaning if you'd rather type out :100: rather than typing :100: then it becomes an emoticon, you can disable it in "/emoticons".
Fork
This addon is a continuation (or a sideproject) of StewartA's addon: http://wow.curseforge.com/addons/smilies/. It's abandoned, hasn't been updated for two expansions, and basically 90% of the code belongs to him, with minor changes and edits. All thanks to him.
FAQ
Yes, the emoticons have to be that small. No, you can't just make them bigger. No, I can't make them bigger. No, they can't be animated. No, not all emoticons look equally great. Yes, there are a lot of memes. Yes, it is very cancerous. Yes, it can be spam-ish. No, I won't take the addon back. No, I won't remove the addon. No, I won't take responsibility if someone (Engineer) becomes more cancerous. No, I won't answer every mail I get in-game, nor add every emoticon suggested. Yes, this is made for ToD. Yes, this is made by someone on ToD. Yes, this is made by Snack. Yes, you can fork this project and make your own version. No, this code is not optimized to function best possible. No, this addon doesn't eat up all your memory. No, I can't control your character with this addon. No, I can't take over your PC with this addon. Yes, I will add more emoticons as time goes on. No, this is not the full FAQ, ask yourself the rest of the questions.