One of my oldest SL friends is, or was, seriously into Gor, and was one of their better-known maker of silks and suchlike.
From how she describes it, it's a whole lot of different subsets of RP -- some people are primarily into combat and capture RP vs each other or with panther girls, some are into master/slave rp, and some into just freeform improv RP, which she usually turned into comedy one way or another (Oh, forgive this stupid girl, Master! When you said such-and-such, she foolishly thought you meant to do whatever she's just done that you're complaining about).