linked documents are ranked by observing link selections for referred documents from referring documents and counting such selections . the counts for each of the link selections are stored at various computer systems of a distributed network , a centralized collection of computers connected through a local network , or a hybrid system consisting of combinations of distributed and centralized systems , and processed to obtain page ranks for the referred documents . the link selections may be observed by a browser extension running on individual ones of the computer systems of the distributed network and the counts of the link selections may be stored at locations within the system determined by a distributed hash table . search request results may be displayed in a ranked order as determined by the page ranks .