The presentation is based on Lahti’s doctoral dissertation, which deals with online discussions of immigration in Finland. The data of the study is collected from the Finnish online discussion forum Suomi24 (“Finland24”), and the data dates from August 2015, when the number of asylum seekers coming to Finland was growing very fast.

The study investigates how argumentation and a shared view of the world are jointly constructed by the discussants. Whereas in previous studies the focus has often been on the representations of immigrants in different media and political texts, the main focus of this study is on the joint construction of argumentation and the interaction between the discussants in social media. The findings show that discussants who are against immigration strongly support each other and that a shared view of the world is collectively constructed by the anti-immigration discussants when the argumentation is based on presuppositions and reasons that are considered as commonly known.