See: What Everyone Needs To Know About (Second) Life “On The Cloud
This article is set in the context of SL but the explanations are about Cloud use and server side rendering. Also, there is explanation about the nuances of some of the 'Lindens' statements on whether SL will have server side rendering.
I find this interesting because I think it could mean an easy way to have Mac and Linux compatible MOUL.
This quote reveals a major reason for rendering to move to the server side.
Another boon to server-side rendering would be the virtual impossibility of content theft. As it stands now, everything you come in contact with in Second Life is sent to your computer (and everyone else’s), so that it may be rendered. If the rendering is done someplace else, that content is no longer being distributed to residents, let alone anyone who would want to steal it.