A method and a carrier medium carrying computer code to execute a method. The method includes defining a set of topics for attachment to one or more information items by at least one user (a registered searcher), the defining the topics including accepting from at least one user at least one topic, and adding the topic to the plurality of topics. The topics do not necessarily have a hierarchical structure. Each topic is for attachment to one or more information item. The attached topics are for searching by a particular searcher for information item(s) according to search request information, including at least one topic of the set of topics, the searching including identifying at least one information item that has attachment to the topic(s) of the search request information. The method further includes defining a collection of attachments that can be viewed and searched by a corresponding group of at least one user, the corresponding group defined for the collection. Each attachment in the collection being between a topic and one or more information items.