[shravan]

In effect, we have exactly this if your acquaintance's contact information is on Facebook and you link your phone's address book with them. You don't need to keep track of constantly changing information since it's all centralized in one location. The "spheres" you reference are akin to Google+ circles or Facebook's lists. You can set the visibility of your contact info to achieve something pretty close to what was described.

The upside of such an approach is that there is one central point of truth for everyone's info. Conversely, the downside is there's also one central point of failure.

[chmike]

My feeling is that we need a neutral and decentralized service for that like the DNS. I want this information hosted in my country and subject to the laws of my country and as a free service like the phone white pages companion of an internet access. Protocol should be open and an internet protocol if a new needs to be defined.

Facebook and Google+ are definitely not the final answer to that need.

[smilekzs]

DNS can be polluted. Again, welcome to China.

Something more decentralized, maybe.

[chmike]

I meant DNS like in the sense of distributed key value database. It should integrate authentication, remote modification capability, etc. I wouldn't use the DNS as is because it wasn't design for that. Such a distributed key value database is easy to implement. The problem are the associated indexes that would be needed. How do we make them distributed and secure ?