While I personally have little interest in virtual BDSM, it does merit study as an aspect of the history, as an example of creating shared fantasy worlds. There’s a new academic paper studying this particular sub-subculture, Topping from the Viewfinder: The Visual Language of Virtual BDSM Photographs in Second Life” by Shaowen Bardzell.
From the abstract:
Photographs were sampled from thousands of user profiles of Second Life users who explicitly associate themselves with one or more BDSM communities or groups. Using visual analysis and social semiotics, I describe the visual language of these images, and with them, the grammar and symbolism of power and submission, of individual and institution, and of photographer and viewer.