search engine retrieval of changing information
In this paper we analyze the Web coverage of three search engines, Google, Yahoo and MSN. We conducted a 15 month study collecting 15,770 Web content or information pages linked from 260 Australian federal and local government Web pages. The key feature of this domain is that new information pages are constantly added but the 260 web pages tend to provide links only to the more recently added information pages. Search engines list only some of the information pages and their coverage varies from month to month. Meta-search engines do little to improve coverage of information pages, because the problem is not the size of web coverage, but the frequency with which information is updated. We conclude that organizations such as governments which post important information on the Web cannot rely on all relevant pages being found with conventional search engines, and need to consider other strategies to ensure important information can be found.
search engine web coverage overlap of web search results