It is a word or a phrase used to search certain topics or themes within the web. Keywords can be insert inserted into a search engine or a database. Using a very specific keyword should lead to a narrow number of results, that shoudbe answeringto the aim of the search.
shoudbe answering to the aim of the search: should answer according to the search aim
What about talking about HOW the keywords are inserted in the database, and WHO could do it (authors, librarians...)?