India is Entering Mobile ID Era, You can call it MID, just like UID, A Single mobile number will do for life. I don't know what after life.
Mobile Number Portability means retain a single mobile number, don't you smell UID Number. Doesn't it ringing like Aadhaar Number.
Today the Dr. Manmohan Singh the Indian Prime Minister will launching the Mobile Number Portability in India.
There are a whole lot of Mobile Operator Companies in India, Each one has its own plus and minus some time a mobile company Sims too good in some area while on other time it is another one.