Most studies use survey data to study peoples prejudiced views. In a digitally connected world, research is needed on out-group sentiments expressed online. In this study, we show how one can elaborate on existing sociological theories (i.e. group threat theory, contact theory) to test whether anti-immigrant sentiments expressed on Twitter are related to sociological conditions. We introduce and illustrate a new method of collecting data on online sentiments, creating a panel of 28,000 Twitter users in 39 regions in the United Kingdom. We apply automated text analysis to quantify anti-immigrant sentiments of 500,000 tweets over a 1-year period. In line with group threat theory, we find that people tweet more negatively about immigrants in periods following more salient coverage of immigration in the news. We find this association both for national news coverage, and for the salience of immigration in the personalized set of outlets people follow on Twitter. In support of contact theory, we find evidence to suggest that Twitter users living in areas with more non-western immigrants, and those who follow a more ethnically diverse group of people, tweet less negatively about immigrants.

Research on Muslim minorities in western societies has mainly focused on offline behavior, such as mosque attendance, whereas little is known about their presence in the online world. This study explores the online visibility and activities of all (478) mosques in the Netherlands. We collected data on personal websites and four social media platforms (Facebook, Twitter, Instagram and YouTube). The majority of mosques have a website (52%) and an account on Facebook (61%). Less often used are Twitter (17%), Instagram (17%) and YouTube (19%). On social media platforms, mosques strongly differ in their activity and number of followers. We find evidence to suggest that Salafist mosques, which tend to have a strict ideology, are more active on Twitter and YouTube, and also attract a larger share of followers on Facebook than non-Salafist mosques. Our more fine-grained analysis on Twitter shows that Salafist mosques in the Netherlands cluster together. Followers of Salafist mosques make up a community of users who are mainly connected to each other ("bonding ties"), and much less so to other users ("bridging ties"). We conclude with a discussion of opportunities for studying the online presence and activities of mosques and Muslims in western societies.