Table 1.

Primary domain classes.

Organization	Meant in a broader sense, including foundations, associations, and unions. These are sometimes professional and often promote some kind of agenda.
Commerce	Private business selling products or services that do not include treatment.
News	Commercial news providers.
Other	Various content not fitting into the other classes.
Personal	Static content from a single person.
Scientific	Sources of scientific work and knowledge including Wikipedia. We included the latter in this class, because its reliability was established in [35]. We believe that Wikipedia, in contrast to sources from other classes, is perceived as a factual source by most of the users.
Social	Social media websites revolving around communication and user-generated content.
Health care providers	Doctors’ offices, clinics, Q&A by professionals. Not limited to Multiple Sclerosis.