Search engines gives the direction to the search. They collect the information, organize it and make it accessible as per your query.
So, what is it that makes one search engine better than other. Why does Google provides different search results than Yahoo for the same keywords and phrases. In other words, what are the various parameters that define relevance of a web page for a keyword and how are these parameters differ in different search engines.
Here is a list of some important parameters :
- Search engine class : Type of search engine make a difference in the search results. Some search engines are Crawler-Based search engines like Google & Yahoo , some are Human-Powered directories, such as open directory and some are Hybrid search engines, like MSN. Their different way of processing create the difference in the search results.
- Relevancy algorithm : Every search engine has its own unique relevancy algorithms ( The mathematical equation for sorting the results), which set the order of results for the search engine query.
- Paid inclusion programs : These programs makes the organic search results more commercial. In this service, the web owner need to pay a flat fee for placing their web page in the top ranking of search engine result pages. For example, Yahoo! has its own paid inclusion program.
- Time frame and age : Search engines have their own parameters of ranking the sites as per the time frame and age of the web site. Like, Google trust old sites than the new ones, however, you can find the new websites in the organic results of MSN Search.
- Crawl depth : It simply means how deeply search engines are moving through the web pages and how much weightage they are giving to the other factors like link quality etc. This is also an important factor for determining the rank of the websites. For example, Google's crawl depth determined not only by the link quantity but the link quality as well.
- Link authenticity & Content : Search engines follows different criterion of giving consideration to the link authenticity, content of the site etc. Like, Google is very much concerned for the link authenticity as compare to the MSN.
- Common words : Some search engines puts weightage to the common words, like, prepositions, articles etc. Google does not substantiate the common words that occur in the search query.
- Open directories : Every search engine takes the references from different (own defined) open directories. If your website is listed in these directories, it will increase the web page ranking in the relevant search engine.
In real sense, Google, Yahoo! and other search engines do things differently instead of doing different things. Everyone is unique in his/her way of working, similarly Google is different than yahoo though they are following many basic set of functioning. Like, everyone is using their own bots which crawl the web pages through hyperlinks, then they store these pages in to indexer by considering every page as a separate document. After getting all the relevant web pages they use their own relevancy algorithm for sorting out the relevant results in to descending order of their relevancy.
For more details checkout these links