Wikipedia as a time machine

Wikipedia encyclopaedia projects, which consist of vast collections of user-edited articles covering a wide range of topics, are among some of the most popular websites on internet. With so many users working collaboratively, mainstream events are often very quickly reflected by both authors editing content and users reading articles. With temporal signals such as changing article content, page viewing activity and the link graph readily available, Wikipedia has gained attention in recent years as a source of temporal event information. This paper serves as an overview of the characteristics and past work which support Wikipedia (English, in this case) for time-aware information retrieval research. Furthermore, we discuss the main content and meta-data temporal signals available along with illustrative analysis. We briefly discuss the source and nature of each signal, and any issues that may complicate extraction and use. To encourage further temporal research based on Wikipedia, we have released all the distilled datasets referred to in this paper