  Members of a society can be characterized by a large number of features, such
as gender, age, ethnicity, religion, social status, and shared activities. One
of the main tie-forming factors between individuals in human societies is
homophily, the tendency of being attracted to similar others. Homophily has
been mainly studied with focus on one of the features and little is known about
the roles of similarities of different origins in the formation of communities.
To close this gap, we analyze three datasets from Information and
Communications Technology (ICT) services, namely, two online social networks
and a network deduced from mobile phone calls, in all of which metadata about
individual features are available. We identify communities within egocentric
networks and surprisingly find that the larger the community is, the more
overlap is found between features of its members and the ego. We interpret this
finding in terms of the effort needed to manage the communities; the larger
diversity requires more effort such that to maintain a large diverse group may
exceed the capacity of the members. As the ego reaches out to her alters on an
ICT service, we observe that the first alter in each community tends to have a
higher feature overlap with the ego than the rest. Moreover the feature overlap
of the ego with all her alters displays a non-monotonic behaviors as a function
of the ego's degree. We propose a simple mechanism of how people add links in
their egocentric networks of alters that reproduces all the empirical
observations and shows the reason behind non-monotonic tendency of the
egocentric feature overlap as a function of the ego's degree.
