Buried in a press release on Yammer momentum are a couple of new details about Microsoft's plans for integrating Yammer with SkyDrive Pro and Office Web Apps by summer 2013.
From the February 20 press release:
"SkyDrive Pro was previewed at the recent SharePoint Conference, and Yammer is implementing it as the underlying platform for file storage. In addition, Yammer is enhancing the ability to preview and edit files directly within Yammer feeds using Office Web Apps. The combination of these capabilities will dramatically enhance a user's ability to create, collaborate, share, and discover content within Yammer. … Read more