WinAzure_rgb_Blk_DAt Microsoft, we have been on a transformative journey to cloud computing and we have been working with customers every step of the way. Millions of customers have embraced the cloud and we are excited to share the news that we’ve reached a major milestone in cloud scale computing.  Since the inception of the authentication service on the Windows Azure platform in 2010, we have now processed 200 BILLION authentications for 50 MILLION active user accounts. In an average week we receive 4.7 BILLION authentication requests for users in over 420 THOUSAND different domains. This is a massive workload when you consider others in the industry are attempting to process 7B logins per year, Azure processes close to that amount in a week.

See the full story at http://blogs.msdn.com/b/windowsazure/archive/2012/11/27/windows-azure-active-directory-processes-200-billion-authentications-connecting-people-data-and-devices-around-the-globe.aspx.