Are they? For sure they have the largest market share, but isn't lack of substitute goods a necessary condition for monopoly? IANAL, but I use Bing all the ti

Are they? For sure they have the largest market share, but isn't lack of substitute goods a necessary condition for monopoly? IANAL, but I use Bing all the time on IE9 because it's the default search engine and most of the time I can't even tell the difference. I certainly haven't found a reason to change it.