Abstract:
A search engine has a query server (50) arranged to receive a search query from a user and return search results, the query server being arranged to identify one or more of the content items relevant to the query, to access a record of changes over time of occurrences of the identified content items, and rank the search results according to the record of changes. TMs can help find those content items which are currently active, and to track or compare the popularity of content items. This is particularly useful for content items whose subjective value to the user depends on them being topical or fashionable. A content analyzer (100) creates a fingerprint database of fingerprints, to compare the fingerprints to determine a number of occurrences of a given content item at a given time, and to record the changes over time of the occurrences.