  Ego networks have proved to be a valuable tool for understanding the
relationships that individuals establish with their peers, both in offline and
online social networks. Particularly interesting are the cognitive constraints
associated with the interactions between the ego and the members of their ego
network, which limit individuals to maintain meaningful interactions with no
more than 150 people, on average, and to arrange such relationships along
concentric circles of decreasing engagement. In this work, we focus on the ego
networks of journalists on Twitter, considering 17 different countries, and we
investigate whether they feature the same characteristics observed for other
relevant classes of Twitter users, like politicians and generic users. Our
findings are that journalists are generally more active and interact with more
people than generic users, regardless of their country. Their ego network
structure is very aligned with reference models derived in anthropology and
observed in general human ego networks. Remarkably, the similarity is even
higher than the one of politicians and generic users ego networks. This may
imply a greater cognitive involvement with Twitter for journalists than for
other user categories. From a dynamic perspective, journalists have stable
short-term relationships that do not change much over time. In the longer term,
though, ego networks can be pretty dynamic, especially in the innermost
circles. Moreover, the ego-alter ties of journalists are often
information-driven, as they are mediated by hashtags both at their inception
and during their lifetime. Finally, we found that relationships between
journalists are assortative in popularity: journalists tend to engage with
other journalists of similar popularity, in all layers but especially in their
innermost ones.
