I was recently asked about Yammer and SharePoint integration by a customer and I got some information which I had sent them. Just for a reference here is that info:
Then this morning as I was driving in it hit me that if you want on-prem Microblogging, look no further then SharePoint 2013 Newsfeeds, I believe that the SharePoint Product Group is positioning that as the MicroBlogging platform within the enterprise. Some of the features that you will see:
We are already using this technology at Microsoft and I think it looks great.
Overview of microblog features, feeds, and the Distributed Cache service in SharePoint Server 2013
Configure microblogging in SharePoint Server 2013