Modern web UI is nice, but at the end of the day when it comes to mobile, apps are still king.
If the purpose of this is to replace the interaction we had on Yammer, a mobile app is a necessity...
Also, feeling a bit frustrated as I have been trying to use the new network on my phone. I typed out a long response to a post, accidentally swiped down too far to scroll up and it force refreshed my browser and lost my whole response...