This is not specifically a Second Life ring, though one might think of it as one, given the collection of sites in it and the fact that almost all of the images appearing on the twitter this ring shares with the Virtual Reality Directory groups (look to your right) are from Second Life. As long as a virtual world offers Second Life like functionality or better (your avatar can move around in it, voice is an option and one can construct objects within it), it is on topic for this ring.
Now that I've bored you to a respectable degree, would you like to visit the ring and see what's on it, so far?