But why?  Really, is there any fundamental reason we should expect Google to remain perpetually on top of the search engine business?<p>I think the difference in quality between Google and Bing search results is negligible; at this point it's just a matter of mindshare as to whether people, on average, go to www.google.com or to www.bing.com when they want to look something up.  There's no vendor lock-in propping up Google, to the extent that there is behind the Windows or iTunes monopolies.  Mindshare can be altered, Microsoft just needs to figure out how to do it.