And so they have attacked this problem by sorting results on an algorithm which seeks to weight relevant items based on a formula of criteria. Items which best meet the criteria are presented to the user, usually by displaying the most relevant ones first. Relevance or results ranking is based on a computer algorithm which has been around for a while. It gained popular recognition on the Internet with Brewster Kahle's introduction of WAIS in the early 1990's. Given these factors, the algorithm gives each of the items a weighting and then ranks them accordingly.
Results ranking is an automated function, without human mediation or intervention.
On the average, it is a fairly useful tool which helps users confronted with large results sets. However, there are some issues which should be taken into consideration. The premise behind weighting occurrences of a given term, is that the more it is used, the more relevant the document. Thus, this paper would likely be given a lower weighting on that phrase, even though conceptually it discusses the larger topic of relevance, which might be of interest to someone searching on that phrase. Again, the more subject expertise a person has, the more likely they are to use precise terms in a search and be able to discriminate on the pertinence of results retrieved.