what is "opensim" ?

[Ansariel Hiller 1,016]

http://opensimulator.org/wiki/Main_Page

[Ansariel Hiller 1,016]

http://opensimulator.org/wiki/Main_Page

[valerie Inshan 5,259]

http://www.hypergridbusiness.com/2012/08/linden-lab-cuts-viewer-link-to-opensim/

http://en.wikipedia.org/wiki/OpenSimulator

[Lindal Kidd 18,058]

OpenSim is an open source virtual world server.  It produces a world that appears similar to Second Life, and many SL viewers will work with OpenSim.

You can run OpenSim on your computer at home and create your own private little virtual world.  Or you can visit any of several OpenSim based grids.  Some of these are "closed" worlds like Second Life, e.g. Inworldz.  Others are interconnected into a "Hypergrid", and you can move from one world to another.  One example of this is OSGrid, which allows you to set up a region on your computer and run it as a part of their world grid, for free.

None of the OpenSim grids are anywhere near as large, rich, or vibrant as SL.  Also, in my opinion, none of them are as stable.  As buggy as we sometimes find SL to be, the OpenSim worlds are worse.

The "OpenSim capable" function of a viewer has absolutely no bearing on how well it works with Second Life.