An avatar is a digital representation of oneself. Some examples of this can be found in videogames, where the user or gamer navigates a virtual world, whether visual or textual, to complete a goal or task. For example, in the videogame Super Mario, the user is in control of an avatar of short italian man wearing overalls. The user has no control over the physical attributes of this avatar, however. In the computer game, The Sims, users have control over what the character looks like from a limited selection of physical attributes including facial features, clothes, hair color, etc. The game is still linear, and the user is still bound to a linear game plot and tasks that they have to do. Finally, in the online RPG called World of Warcraft, users have total control over what their character looks like and the actions that their character does ingame, along with interacting with other online avatars representing characters.
A digital identity is the way one chooses to portray themselves on a certain website, blog, online game, etc. For example, Mark Stephen Meadows's work, I, Avatar, there is an example of three girls who chose to give themselves false identities on youtube. They claimed to be people that they weren't, taking on a totally different identity than they possess in the real world. People have a separate ego when it comes to online interaction and activity. On blog sites, people may say words and phrases to other users that they would not say in real life. The digital Second Life allows them to hide behind a mask that is their avatar and their username.