Blue Mars by Avatar - is another MMORPG/VW environment on the block. Eventually giving developers a big set of tools to create a wide range of online experiences. Blue Mars creates a unified login system, allowing your avatar to move between diverse Virtual Spaces using the same tech.
Montage of the Blue Mars demo spaces, showing how the technology can be used for a community spaces and games. It uses CryEngine 2 for the graphics, giving some impressive shaders for high quality graphics in a VW. Lots of potential for developers to create rich environments and online game content.
For Educators, this is no SL replacement in terms of casual idea development and experimenting.. it is a Dev Heavy technology, but has bags of potential for some Serious Games, or creating visually rich virtual campuses.
Also its now a good opportunity to consider bringing in students/staff on Games Design / Digital Media courses to help develop content for other departements.
Its hard to judge how useful Blue Mars will be based on these Demo's, as ultimately you can create whatever space you want, so its now down to some exciting developers and community building stuff going on, if it is to succeed.
Of the short time I've played with it , and looked at the other BM preview tools, my vibe is that it is more comparable with Multiverse - http://www.multiverse.net/index.html , than Second Life.
Also if you want to get a good feel for Blue Mars - you could also get a copy of Crysis for your PC ( which you can find in the bargin bin now ) - as it comes with the Sandbox Editor modding tools, that allows for machinima making too. - here's an example - http://www.youtube.com/watch?v=8R_i-0lZoj4