Since Yammer already supports a integration with SharePoint we will just have to wait and see if it will be integrated in SharePoint 2013 (SharePoint 15).
Yammer also send a e-mail to all his users informing them about the acquiring by Microsoft.
Dear Yammer Customer,
I am pleased to announce that Yammer has signed a definitive agreement to be acquired by Microsoft. After the close of the deal, Microsoft will continue to invest in Yammer’s freemium, stand-alone service, and the team will remain under my direction within the Microsoft Office Division. With the backing of Microsoft, our aim is to massively accelerate our vision to change the way work gets done with software that is built for the enterprise and loved by users.
As a Yammer customer, you will continue to get a secure, private social network—delivered with the same focus on simplicity, innovation, and cross-platform experiences. Over time, you’ll see more and more connections to SharePoint, Office365, Dynamics and Skype. Yammer’s expertise in empowering employees, driving adoption, and delivering rapid innovation in the cloud will not only continue to power our stand-alone service, but also anchor the communication and collaboration experiences in Office 365.
Yammer CEO and Founder