This study reports the findings of a comparison between traditional and online data collection methods. Respondents were recruited in four different ways, namely from an online opt-in panel, via website pop-ups, by postal mail and by telephone. The response patterns from different data collection methods relating to a variety of subjects (e.g. internet use, technology adoption, attitudes, interests and opinions, demographics) are compared. The results indicate that all sampling methods generate different results (also between postal and telephone research) when not controlling for socio-demographics from the national population. Once controlling for such factors, online and offline data collection methods generate similar results in terms of socio-demographics, attitudes, interests and opinions. Although some differences remain they can not be attributed to one or the other recruitment method. Correcting post hoc via reselection reduces the differences considerably in terms of technology adoption, while clear differences remain in terms of internet usage behaviour. Post hoc reselection showed to be more effective than reweighing for technological topics.