The analysis of deleted or updated Web pages

Abstract

　The importance of web pages as information sources has grown larger as the number of pages has been increasing rapidly. Web pages, however, are not considered as a reliable information sources since they have short life and about half of them are deleted or updated in a year. But, a part of the pages considered as deleted or updated are often moved to other servers or only change their URLs. We have found that about 30 or 40% of the pages considered missing still exist and are even traceable and can be reached by analyzing the pages considered missing. We have found out 23.6% of the pages considered deleted by making the program which can trace the pages by using URL structures and keywords in title, center and selection tags.