By the time Microsoft got in the search game the web graph was polluted with spammy and bought links.
This article will hopefully help searchers understand the different relevancy criteria used by different engines.While some machines automatically evolve search relevancy via genetic algorithms each major search engine still has some human input in how relevancy is calculated (at the very least humans write some of the algorithms). Diaz wrote a PDF research paper about Google's biases. For many years they outsourced their search service to other providers, but by the end of 2002 they realized the importance and value of search and started aggressively acquiring search companies. has a boatload of their own content which they frequently reference in the search results.Originally when I started writing this article I wanted it to be more about search relevancy perhaps from more of an academic type standpoint, but my perspective on search is as one who understands it more from a marketing perspective. Since they have so much of their own content and make money from some commercial organic search results it might make sense for them to bias their search results a bit toward commercial websites.MSN has got better at crawling, but I still think Yahoo! It is best to avoid session IDs, sending bots cookies, or using many variables in the URL strings. or Google at crawling deeply through large sites like e or at processing queries for meaning instead of taking them quite so literally, but I do not believe they are as good as Google is at it.While MSN offers a tool that estimates how commercial a page or query is I think their lack of ability to distinguish quality links from low quality links makes their results exceptionally biased toward commercial results.