I spoke to Gelernter at a conference, ages ago. His wares were being compared to JavaSpaces. IIRC, maybe because he had done some work on Linda, or his lifestreams was implemented using same, or something like that. No one really grokked what lifestreams was about or how you'd use it. (Jini and JXTA suffered similar befuddlement.)

Any way, I over enthusiastically encouraged him to repurpose lifestreams into a PIM (personal information manager, shows how old I am) unifying all one's communication and activities. To Gelernter's credit, he listened seriously and pondered.

I'm still waiting. :)