Overview of the INEX 2012 Tweet Contextualization Track.

The use case of the Tweet Contextualization task is the fol- lowing: given a new tweet, participating systems must provide some con- text about the subject of a tweet, in order to help the reader to under- stand it. In this task, contextualizing tweets consists in answering ques- tions of the form \what is this tweet about?" which can be answered by several sentences or by an aggregation of texts from dierent doc- uments of the Wikipedia. Thus, tweet analysis, XML/passage retrieval and automatic summarization are combined in order to get closer to real information needs. This article describes the data sets and topics, the metrics used for the evaluation of the systems submissions, as well as the results that they obtained.