Geography plays an important role in shaping societal interactions in the offline world. However, as more and more social interactions occur online via social networking sites like Twitter and Facebook, users can interact with others unconstrained by their geolocations, raising the question: does offline geography still matter in online social networks? We attempt to address this question by dissecting the Twitter social network based on users' geolocations and investigating how users' geolocation impacts their participation in Twitter, including their connections to others and the information they exchange with them. Our in-depth analysis reveals that geography continues to have a significant impact on user interactions in the Twitter social network. The influence of geography could be potentially explained by the shared national, linguistic, and cultural backgrounds of users from the same geographic neighborhood.

Geographic Dissection of the Twitter Network
Juhi Kulshrestha, Farshad Kooti, Ashkan Nikravesh, Krishna P. Gummadi International AAAI Conference on Weblogs and Social Media (ICWSM), Dublin, Ireland, June 2012.