Ironically, one of the first searches I did resulted in an article from the Google Help page all about how they use a pigeon system to rank information for relevancy! At first I thought the article was true and that they were just using pigeons as a metaphor for their system. But it seemed too spoofy so when I scrolled down to the bottom to see more information the date said April Fool's Day 2006! I should have checked that first!!! Ha ha!
I found this inquiry very interesting and think the knowledge I have gained will be useful when facilitating internet searches with my students. I find it interesting that Yahoo and Google say they are not manually manipulating the relevancy ratings but yet put the paying sites appear first, which in my mind is a contradiction. However, I understand that they mean that they don’t manipulate the ratings on the sites that come after the paid sites, but still I find this to be a little bit deceptive, especially when you consider the age or skill level of some its users. I know the paid sites at the top of the list are marked with a different color and therefore even a non discriminating user should be able to figure this out, so I will let it go. But I’m just sayin’!
Google
Google uses a collection of algorithms to determine relevancy and these algorithms are updated and changed every day to increase relevancy. One interesting algorithm is called the Caffeine Web Indexing System which allows Google to crawl and index sites to determine how the date of the information should impact its relevancy. For example, if one searches a sports team score it will start rank most recent game scores higher, but if searching a recipe, the most recent recipe will not necessarily be ranked higher. Using the Advance Search Option is an incredible way to increase the relevancy of the searches because you can limit your results to exact phrasing, readability level, material type, language, and many more ways. Google has three basic philosophies behind their ranking system: keeping the best relevant results local globally, keeping it simple so that their engineers understand clear criteria, and using no manual intervention on their part. They say that to keep their rankings reliable they have policies written for websites and they take action on sites that are in violation of their policies.
Yahoo
I found it much more difficult to get information from Yahoo about how it determines relevancy. The only way that I was able to find information about this topic was by looking at their tips page for increasing the ranking on your webpage. I also looked at some articles comparing different search engines and pieced together that similar to Google, Yahoo also has algorithms that they use for ranking searches. They look at content, titles, keywords, and links to other content that is related to the search terms to determine relevancy. They use spiders for their indexing and do not manipulate the results manually. They also have controls in place to deter manipulation of their ranking system. Yahoo also has an advance search option but it is more limited than Google’s.
DMOZ Open Directory
I had never heard of DMOZ Open Directory and it is quite different than Google and Yahoo because it is maintained by humans rather than digital spiders and digital indexes. Volunteers who use DMOZ Open Directory organize the web and determine the rating of content on the web. Anyone can be a volunteer to determine this and so this is search engine ranked and classified by the global community. It is founded in the open source movement and will always remain free. The Open Directory does not have an advanced search option.
To make a personal comparison I entered the search term “frogs” (I’m a grade one teacher) using all of these search engines. I found that Google and yahoo yielded similar results and I would determine them to be reasonably useful and relevant. The DMOZ Open Directory however yielded results that in my opinion were less useful and relevant. Overall I would say that personally I enjoyed using Google the most because of the ease in using its advanced search options.
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