Is there a hard boundary to a group?

One of the problems being faced by the advent of lots of data is trying to understand what are the new relationships and boundaries!  What does everyone know and what does someone know that no-one else does? What does someone have that is slow to get again? What data can I get or collect from you very quickly?

Given that everyone has the same data on you, why can they not share this and make my life easy!  What makes you think that I will be more loyal to you because you know more?

There are no easy boundaries, no clean firm and hard separation in segmentation and it likely that we need to rethink how we group people based on the creation of complex mashups of data that will create a movable pen rather than a fixed boundary that was based on easy but sloppy and overlapping ideals of demographics.