Sit back, watch the video
I’m not quite sure, yet, what I think of it, but putting the “Can it really be realised/implemented?” question aside, his idea really sounds stamin! I’ll definitely will have an eye on it and would love to see those ideas aroused!
By the way, the Drupal module it obviously started with is Activity Stream.
Side note: What do I tag this with? Where is wordpress’s option for the infinity-all-possible-ever-thought-of-tag?