City of Disguise: A Query Obfuscation Game on the ClueWeb

We present City of Disguise, a retrieval game that tests how well searchers are able to reformulate some sensitive query in a 'Taboo'-style setup but still retrieve good results. Given one of 200 sensitive information needs and a relevant example document, the players use a special ClueWeb12 search interface that also hints at potentially useful search terms. For an obfuscated query, the system assigns points depending on the result quality and the formulated query. In a pilot study with 72 players, we observed that they find obfuscations to retrieve relevant documents but often only when they relied on the suggested terms.