The purpose of ALT text is to describe the image for the benefit of those who surf the Web with images turned off and for those who have the contents of Web pages read out loud to them. The WC3 highly recommends that Web site owners use ALT text to describe images. ALT text was just one piece of 100 different factors to determine ranking.
http://forums.seochat.com/google-optimization-7/images-and-seo-268888.html
Forming an SEO Monopoly is the most powerful thing a company can do to center themselves in the organic search results.
