Now that there's more tighter integration between SharePoint and Yammer - how should Yammer-related questions be addressed? Should they be referred to the Yammer Support forums or other Yammer public sites ?
We already have a yammer tag, with five questions. So fire away - ask your yammer questions, as long as they are related to SharePoint. Otherwise, you'd have better chances at the yammer forums you mention.
SharePoint and Yammer seems to be more and more merged together in what Microsoft refer to as their "Social Layer" that will span most of their products.
To me I would therefore gladly see questions about Yammer posted here on SP.SE, it is surely within the scope of the community and I bet that many of out members has valuable knowledge regarding it :)