A documents database has a plurality of documents, including but not limited to text files, video clips and sound files. Each document is associated with at least one category of a plurality of categories in a categories database, and each category has at least one keyword. A search request having at least one search term is received from a user, and a categories database is searched for categories having a keyword corresponding to the user search term to identify first level categories. The other keywords from the identified first level categories are retrieved and the documents database is searched for documents having a user search term or a retrieved keyword. The identified documents are then ranked and presented to the user. Other search expansion techniques, and display techniques, are also discussed.