A person that enjoys the art form of making emotes (or emoticons). Emoticonists go far beyond what many of us call them such as :-) or XD by making fully animated or static designed graphics.
Some emotes are not though designed for general chat use. Emotes can be big, small, or have a fully designed background made with only a 1 pixel brush 90% through the way.:D
Many of these "Emoticonists" can be discovered on the popular art site deviantART, though, not only members of that site may make emoticons.
Go to deviantART.com and search "Emote" or "Emoticons" to find some really good emotes and Emoticonist(s).