Abstract: The present invention is a method and system for searching for items on a computer network, such as the internet, based on a query and an exclusion specification comprising a specification of a characteristic of sources of the items, to create a list of identifiers of items relevant to the query that are not excluded by the exclusion specification. Such characteristics include measures of popularity of the sources of the items so that items from sources having popularity greater than the specified popularity may be excluded from the list.