  Religious beliefs could facilitate human cooperation [1-6], promote civic
engagement [7-10], improve life satisfaction [11-13] and even boom economic
development [14-16]. On the other side, some aspects of religion may lead to
regional violence, intergroup conflict and moral prejudice against atheists
[17-23]. Analogous to the separation of races [24], the religious segregation
is a major ingredient resulting in increasing alienation, misunderstanding,
cultural conflict and even violence among believers of different faiths
[18,19,25]. Thus far, quantitative understanding of religious segregation is
rare. Here we analyze a directed social network extracted from weibo.com (the
largest directed social network in China, similar to twitter.com), which is
consisted of 6875 believers in Christianism, Buddhism, Islam and Taoism. This
religion network is highly segregative, with only 1.6% of links connecting
individuals in different religions. Comparative analysis shows that the extent
of segregation for different religions is much higher than that for different
races and slightly higher than that for different political parties. The few
cross-religion links play a critical role in maintaining network connectivity,
being remarkably more important than links with highest betweennesses [26] or
bridgenesses [27]. Further content analysis shows that 46.7% of these
cross-religion links are probably related to charitable issues. Our findings
provide quantitative insights into religious segregation and valuable clues to
encourage cross-religion communications.
