Personalizing a search of a search service

The invention relates to a method for personalizing a search of a search service. The search service comprises a search index with content items of a search type being used as first search results for first search queries issued by the client application and providing second search queries to be executed for retrieving second search results to be returned in reply to the first search queries. The method comprises using information specifying external content items imported by the client application to amend a set of content items for extracting one or more keywords comprised by the imported external content items. A second search query suitable for retrieving the set of content items being amended with the imported external content items is determined. The determined second search query is modified by adding the extracted keywords as additional search parameters.