I'm not an expert of this.  However, I think I know the motivation
of IBM's VM attempt.   Because they decided their main job as
"ON DEMAND" business.   To do this, they need such a frexible
mechanism to offer various on demand, on line business.

However, this is Plan 9 community.   Is their anyone trying to
make on demand business? ☺

By the way, anyone Plan 9ers here is invlolved in the development 
of DeepMail?

Kenji