News Center Story:

http://www.microsoft.com/en-us/news/Press/2012/Jul12/07-16OfficePR.aspx

Office Next Blog:

https://twitter.com/Office/status/223835852218970112

Office Preview:

https://twitter.com/Office/status/224942083742507008

Exchange 2013:

https://twitter.com/MSFTExchange/status/224950039468982275