The Dutch Tax and Customs Administration website is aimed at supporting citizens in fulfilling their tax and customs obligations. In 2002, it was decided to implement a enhanced search service. A commercial topic map engine was used to centralize management and control of keywords. A closed-loop process was implemented, connecting site visitors entering search terms with the synonyms used by the search engine and the metadata statements added by authors. While none of the individual components is groundbreaking, the combination is useful and has already been used in other problem domains. The fact that the topic map paradigm is well suited to an evolutionary style of development proved to be an important asset. In this respect, the standardized merging facility was crucial.