Though online social networks are quickly growing extremely
large (Facebook has over 250 million users worldwide), their
mechanisms for establishing person to person relationships
remain quite basic. In symmetrical networks like Facebook and
LinkedIn, a 2-way handshake is required to confirm a
relationship. That is, both sides have to agree to be connected.
In asymmetrical networks like Twitter, a 1-way connection is all
that is required to follow someone's activities. Despite the
clear difference between these social models, I found it
interesting that in both cases, messaging activity reveals a
"hidden" but perhaps more connected social network. In Social
networks that matter: Twitter under the microscope, the authors
found that even Twitter users with a large network of
asymmetrical connections have a much smaller network of friends
that is revealed by messaging activity. This "hidden" network
has 90% reciprocity (mutual friendships) and drives more usage.
While the number of posts as a function of followe