Introduction. Little is known about Wikipedia contributors’ information behaviour and from where and how the information in the encyclopaedia originated. Even though a large number of texts in Wikipedia cite external sources according to the intentions of the verifiability policy, many articles lack references and in many others the references have been added afterwards.
Method. This article reports the results of a Web survey of information source use patterns, answered by 108 Wikipedia contributors in spring 2008.
Analysis. The qualitative questions were analysed using a close reading and grounded theory approach. The multiple-choice questions were analysed using descriptive statistics and bi-variate correlation analysis.
Results. The results indicate that there are several distinct groups of contributors using different information sources. The results also indicate a preference for sources available online. However, in spite of the popularity of online material a significant proportion of the original information is based on printed literature, personal expertise and other non-digital sources of information. The information source use of Wikipedia contributors is also illustrative of the complexity and life-world scope of human information behaviour.
Conclusions. Understanding the information source use of contributors helps us to understand how new Wikipedia articles emerge, how edits are motivated, where the information actually comes from and more generally, what kind of information may be expected to be found in Wikipedia.