As you may already know Yammer – the enterprise social network – is starting to be integrated with SharePoint; this integration is already available to SharePoint Online (see http://blog.hametbenoit.info/Lists/Posts/Post.aspx?ID=523).

So what about customers with SharePoint 2013 On Premises? The answer is here http://www.microsoft.com/en-us/download/details.aspx?id=39357