This paper highlights the potential of three-dimensional multi-user environments such as "Second Life" (SL) from the perspective of future developments in the service of learning. It notes trends within the SL innovation to date, including the provision of realistic settings, the exploitation of pleasant simulated environments for groups and the links with other learning technologies. It also considers the creativity sparked by SL's potential to offer the illusion of 3-D "spaces" and buildings, and points to infinite imaginative educational possibilities. It explores aspects of the construction of virtual representations of learners and teachers as avatars, and reveals a wide range of intriguing issues yet to be researched.