Controls how important frequency in the table is for results ranking.
The more a term occurs in the table being searched, the worse
its rank. Terms that occur in many documents are usually less
relevant than rare terms. For example, in a web-walk database the
word "HTML" is likely to occur in most documents: it thus has
little use in finding a specific document. The default weight is
medium (500). Note that search users can override this setting on
the Advanced search form.