Love this, and have been thinking about it for a while (after having moved literally 10 times in 10 years). I picture something similar to OAuth permissions, where at any point I can revoke access to all or specific pieces of information to anyone.
As an extension (and this is potentially where the money is), I can think of an intermediary service (a-la Google Voice call widgets) that allows entities to contact me without ever giving away my phone/address/etc.
Absolutely. Currently I have zero control over who has what contact details. I have good friends that still email me on an eight year old gmail address that I don't use. I need to be able to pull addresses, push new ones, have certain details only available to certain friends and maybe, like you say, have ways of letting people get in touch with me once without actually giving out my details.
As an extension (and this is potentially where the money is), I can think of an intermediary service (a-la Google Voice call widgets) that allows entities to contact me without ever giving away my phone/address/etc.