Capabilities explained... a Google tech talk worth watching

I highly recommend you watch http://www.youtube.com/watch?v=EGX2I31OhBE which is a Google tech talk video about Object Capabilities, heavy on practical reasons, explanation, and conversational inquiry from the audience.

It might take you a while to unpack all of the jargon that has arisen over the decades of Capabilities based research, but you'll walk away with knowledge well worth the effort.