1)A virtual world is a place where humans live vicariously through their avatars; where they learn by observing the behaviors being modeled by other avatars; where pleasurable or disturbing reactions can be observes; and where attitudes can be affected by immersive role-playing.
2)Challenges that educators face when using virtual words include the learning curve needed to create classrooms and learning materials in the virtual environment, keeping students free of distractions and on task, technical issues, and limited empirical research on the subject.