However, if there are not enough of these, it will present tiers of results corresponding to gradual relaxation of this constraint. Except for rare examples such as IT , case insensitivity produces best results, but an optional case-sensitive feature is on the list of improvements under consideration. Stop words such as the , a , and of occur very frequently in documents and usually slow down query processing while contributing nothing to the quality of results. However, in some cases, eg. to be or not to be they can be important.
Short queries consist of four or fewer non-stopwords.
If any documents contain all of the query words, they will be presented in the top tier of results. Documents which partially match will be presented in subsequent tiers. Within a tier, documents are ranked by their relevance score, which takes into account the relative rarity of the query terms, the frequency with which they occur in the document and the length of the document. In addition, the scores of documents containing the query words in their title or in the URL of the page are boosted. Long queries consist of five or more non-stopwords.