I have wondered this for quite some time but have not found any references. In the TV series "The wire" they use disposable prepaid mobile phones as a counter-surveillance technique. However if someone uses a prepaid mobile phone and connects to the same people as with his old phone, wouldn't this uniquely identify him? For example if Alice knows Bob and also Eric, while Eric lives in a town far away. Now Alice buys a new burner phone and still messages with Bob and Eric, what are the odds that another network user who is not Alice knows Bob and Eric too? I mean only knowing two people - even if Eric lived in the same area as Bob - will greatly reduce the number of suspects. Is this technique used? And where can I read up on it? I'm interested in the technical as well as legal aspects of this method.
One common legal application is in web advertising. Advertisers aren't allowed to have access to your personally identifiable information, but they may have access to your anonymized information and some unique identifiers (usually from cookies or browser fingerprinting). Those unique identifiers can become lost or replaced as cookies expire or are deleted, but by cross-referencing patterns and other anonymized information, it's sometimes possible to draw a conclusion that two different unique identifiers are actually the same individual. In the advertising world, this can be used to identify that two seemingly different people are actually the same person using different devices (e.g. mobile phone, desktop, tablet) without ever actually knowing who the individual is.
That said, it's not always an easy or foolproof process, but it is possible.