The rapid development of Virtual Reality-based technologies over the past decade is both an asset and a challenge for neuro-rehabilitation. The availability of novel technologies that provide interactive, functional simulations with multimodal feedback enable clinicians to achieve traditional therapeutic goals that would be difficult, if not impossible, to attain via conventional therapy. They also lead to the creation of completely new clinical paradigms which would have been hard to achieve in the past. In applications of rehabilitation for both motor and cognitive deficits the main focus of much of the early exploratory research has been to investigate the use of virtual reality as an assessment tool. To date such environments are primarily: (a) single user (i.e., designed for and used by one clinical client at a time) and (b) used locally within a clinical or educational setting. More recently, researchers have begun the development of new and more complex VR-based approaches according to two dimensions: the number of users and the distance between the users. Driven by a push-pull phenomenon, the original approach has now expanded to three additional avenues: multiple users in co-located settings; single users in remote locations; and multiple users in remote locations. After a presentation of examples that illustrate theses various approaches, we will conclude in addressing questions and ethical considerations raised by this evolution in the use of virtual environments in rehabilitation.