  Homophily, ranging from demographics to sentiments, breeds connections in
social networks, either offline or online. However, with the prosperous growth
of music streaming service, whether homophily exists in online music listening
remains unclear. In this study, two online social networks of a same group of
active users are established respectively in Netease Music and Weibo. Through
presented multiple similarity measures, it is evidently demonstrated that
homophily does exist in music listening of both online social networks. The
unexpected music similarity in Weibo also implies that knowledge from generic
social networks can be confidently transfered to domain-oriented networks for
context enrichment and algorithm enhancement. Comprehensive factors that might
function in formation of homophily are further probed and many interesting
patterns are profoundly revealed. It is found that female friends are more
homogeneous in music listening and positive and energetic songs significantly
pull users close. Our methodology and findings would shed lights on realistic
applications in online music services.
