Here is a little attempt to assemble news and informations about IBM's
involvement with virtual worlds. I am not an IBM fanboy, but i think
it is same to assume that they will play a big role in this field (as
will Google if the rumor/possibility   of adapting Google Earth
for massive multiplayer and social interaction is true, Second Earth).
Considering IBM's Second Life experiments, Cell processor involvment
as well as mainframe computing (cf. system z platform ), what could
they do ?
"The company is working on a project to integrate its Cell Broadband
Engine processor with its System z mainframes to create a hybrid
computer that has the power of a mainframe with the 3D graphics
capability of a PlayStation 3." 
Linked with another dot , this means that they will have a graphics
core in the mainframe. Nice: distributed, linux-based, flexible,
level-of-detail-independant (<- gradual monetization and
device-independant rendering) real time high performance (raytracing
!) rendering. Cool, but how do you deliver this to clients ?
This only makes sense if:
* you deliver the rendered content back to the client; i can't see
anything else than TOIP (mpeg-4). This implies on-demand video 3D
rendering (see RenderRocket-IBM  )
* you get his inputs (vnc-like)
Java or even flash could do the trick. Embedding within traditional
webpages (and a lot of web-enabled apps) will be quite easy then.
What about the game/world itself ? There's an interesting link between
IBM and Hoplon, a brazilian game developer  . Mostly because
they are developing (together with IBM) a space MMORPG. Which means
planets, galaxies... Remember Bob Sutor's vision  ?
Heh, they may take this as infrastructure, and every planet within
this world could be a gate to specialized worlds. One planet could be
the "Second Earth", another one could be World of Warcraft, etc... And
what's nice with video rendering is that you could in theory integrate
heterogeneous platforms (Windows games, Linux apps, heterogeneous 3D
technologies etc...) provided they offer some SOA and interoperability
concerning avatar portability, transparent login, unified instant
communication (IM, video, ...). Games could continue the shift towards
pure service (remote rendering IS a value added service...). Computing
in general could (it's already happening on the hosting market -- cf
Amazon EC2 services).
Is remote computing coming back ? Together with the VOD triple play
services (very obvious in France for instance), the video
infrastructure is maturing. Achieving the whole thing < 50 ms will be
tricky, but you know, supercomputers are this common these days ;)
If some of you want to start speaking Cell,  you can already.