Thanks to a lack of convention in taxonomy, virtual worlds = virtual environments = everything online and the proverbial kitchen sink.
I won’t attempt any definition here, but I will try to provide examples of virtual environments and group them in categories of similar attributes. Here Elluminate, Acrobat Connect, Blackboard, Web CT and the likes are NOT considered virtual environments.
provides audio, video and conferencing affordances to attendees.
pay per use
world already developed and ready to use
no user creation (unless you use the developer kit)
limited interaction with objects to conferencing purposes.
tabula raza for imagination, full user creation affordances
audio, video, building, scripting
free support from community (especially in education)
steep learning curve
open to public unless set up private access to location
OpenSim-based worlds: 3rd Rock Grid, Reaction Grid,
Open Wonderland-based worlds
MMORPGs such as World of Warcraft,