Thanks to New World Notes, where I learned of the first crossing of avatars from SL into another grid.

At about 11:00 AM, Linden, Ruth arrived on an OpenSim server
- Zha Ewry

This seems significant.

What it could mean: Soon, parents and school administrators down the street will not have to worry about Mature Content, because they can run their own grid and minors can TP in from the Teen Grid for lessons…