How valuable is external link evidence when searching enterprise Webs

Abstract

Link information, especially anchor text, is known to be very useful for effective ranking of web pages, par- ticularly in response to navigational queries. We in- vestigated whether enterprise webs contain sufficient internal link information to adequately answer queries derived from the enterprise’s site map or, alterna- tively, whether adding link evidence from the external Web can boost search effectiveness. Using 1266 navigational queries derived from Stanford University’s A-Z site index, we found no difference between the quality of results returned by Stanford’s Google appliance and those from an appropriately site-restricted search of the global Google service. Applying similar methodology to our own crawls of seven Australian organisations, we found that adding external link evidence made no significant difference to search effectiveness in five cases and a slight difference (in different directions) in the other two. We observed that external links to an organisation show very different patterns to internal links. Unlike enterprise web publishers, external web authors heavily favour directory default pages, particularly the organisation’s home page and pages offering information or services likely to be useful on an ongoing basis. External links seldom reference the complex, parameterised URLs in common use in many organisations.