Yesterday QuePort, a Microsoft Partner since old times of FAST Search, has released a new App in their Search driven application suite. Currently QuePort is converting many WebParts into Apps which also can be used in O365/SP Online.The new App is called "Newsfeed Notifier", can be found in the SharePoint App Store, and offers a single point of notification for all newsfeed updates. Just imagine you are within a Teamsite and working on a document. You can immediately read the news without leaving the site. You can compare it with notification button you know from Facebook. It also allows you to reply to updates without navigating to the SharePoint 2013 Newsfeed. This is just the initial release. There are more exciting features to come, I can promise.
Find my Slidedeck here about QuePort Integration. It covers features and screenshot of en Premise installation and also Apps for Office365/SharePoint Online. Yammer App for SharePoint is also covered.
QuePort has released more Apps in the meanwhile and this one is for free: Documents shared with me (App Store Link):
Overview of QuePort`s Social Apps (in German), read more