(PLS, WAIS, Verity, Architext)
A ``query by example'' consists in naming relevant documents in a query form to search for other similar documents. The server analyzes the submitted documents and determines which of the words in the documents are useful discriminators. It then uses those words to find other documents which share them. One of the primary uses of query by example is to help users quickly focus their search without the need to learn complex query languages. ``Relevance feedback'' is the ability to select a document or a portion from the list of documents resulting from a first search to find a set of documents related to it.