http://blogs.technet.com/b/lystavlen/archive/2012/07/16/office-web-app-attachment-preview.aspxOutlook Web App now integrates the Office Web Apps into the attachment previewing experience for Word documents, Excel spreadsheets, and PowerPoint presentations. When Office Web App attachment preview is enabled, users see an Open In Browser linken-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)