They are used in virtual worlds to represent yourself. Microsoft had a great program called "V-Chat". It was not well known and experimental. They were 3D chat rooms. I built 12 rooms that were very popular. The avatars they used were in png format. They were similar to gif animations so your character could do wild things. There where several other folks who started similar rooms. The concept was that ultimately one could online actually go shopping in a mall or just chat in 3D. Do a search for virtual rooms or virtual chat. I am sure there are still some around. I lost interest about 1.5 years ago when MS decided not to support it and allowed anyone to use its tech. Porn folks seemed to take over. It was very popular in Europe. Ron