With a tiny 6.76% of the search market, compared with Googles 60%+ search share dominance, Microsoft has decided its time to leverage their massive base of global Windows users with juicy wads of cash to switch search providers!
http://www.itwire.com.au/content/view/10554/532/Microsoft will use a Browser Helper Object installed into IE7 to track search queries and send information on search back to Microsoft, so they can use the information to improve the results that Windows Live Search delivers. Because of this, IE7 must be used it doesnt work with Firefox, Opera or older versions of IE browsers.