interaction is actually anonymised versions of clustering engines exist to cluster known identities and their characteristics but not in the context of anonymising interactions and communications between devices a version to retain the identity within an id brokerage context is novel a user may be alone in a cluster group but their identity as the sole occupant is never known to the service clusters may be u2018 pre prepared u2019 with dummy members before adding real users who are observed to exhibit a characteristic to ensure that there is more than one member to a cluster or dummy members may be added during use as required the clustering is done on abstractions of identities the translation of which to real identities is not known to the clustering engine or its operators human or machine clustering can be in real time or batched into runs the following example is provided by way of further explanation consider an individual who lives in putney london england has had an interest in double glazing an interest in dogs and an interest in mercedes cars this makes the individual a member of a set of individuals and no further knowledge is needed to advertise to them a wide range of products that they also have an interest in cr u00e8ches and rugby bach and tuscany may still not be enough to allow insight into the individual add to this an interest in childhood eczema and it might identify just one family widen the clustering to include neighbouring wandsworth and the u2018 crowd u2019 is restored and hence.