Using the data contained in a database, Users can rapidly search and find relevant information. That data may be stored as keywords.
Keywords are highly focussed on a particular topic or document and are consequently faster at returning search results. Keywords can be allocated to documents by the author / administrator or can be ripped out of the source document and provided automatically.
Keywords can also be exposed to Search Engines in the most effetive manner, to emphasise the relevance/importance of the content.