Microsoft invented the MobileOptimized META tag to control the layout width for mobile markup rendered in Internet Explorer Mobile.
http://msdn.microsoft.com/en-us/library/bb159711.aspx
Mobile
Get access to data on 5,026,359 websites Mobile Optimized Customers. We know of 1,485,855 live websites using Mobile Optimized and an additional 3,540,504 sites that used Mobile Optimized historically and 718,230 websites in the United States.
Get a list of 5,026,359 websites using Mobile Optimized which includes location information, hosting data, contact details, 1,485,855 currently live websites and an additional 1,346,083 domains that redirect to sites in this list. 3,540,504 sites that used this technology previouslyand 718,230 websites in the United States currently using Mobile Optimized.
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