[stebann]

Having read about anonymization techniques I have started to believe that definitions of anonymity and pseudo-anonymity are well settle by now but criteria that contributes to the invariants for performing data transformation are not, so the result is that this criteria fail to guide the implementations of the transformations.

You keep data because data is economically valuable, but even when you care enough to implement some techniques that depends on the invariants you still fail to achieve something the better because of scale and because you don't want to refine the techniques. This also means that somehow somebody may have a technique that, provided enough pieces of data, can reverse you transformation.