Virtual world "residents" and their parents know what avatars are: An in-world representative of you. In Second Life, though some users have more than one avatar, most avatars are quite human-looking versions of users. It depends on the world quite a bit. In ClubPenguin, they're, well, penguins. In a lot of kids' virtual worlds, the avatars are cartoon-y humans with big eyes and heads. In videogames, there's a huge range of virtual selves, from human-like to fantasy creatures with special powers.
I'm telling you all this because a new study indicates that people's avatars can be aspirational or motivational, at least in terms of appearance. It found that "creating a thin and physically fit online avatar may encourage people to become healthier and more physically fit in real life," Triangle Business Journal reports. The study, by RTI International, found that that "80% of respondents who reported high levels of physical activity for their avatars also reported participating in high levels of physical activity in their real lives." The article appeared in the August issue of the Journal of Virtual Worlds Research.