Commons 6.x-2.0 and greater support "microblogging" via the facebook_status module. This is a feature that didn't make it to the MVP for Commons 3.0. This should either be added back into Commons or documented as deprecated.
Meta issue for 6.x-2.x features that didn't make it to Commons 3.0 MVP: #1930406: [Meta] - As a site Administrator I would like to upgrade from 6.x-2.x to 7.x-3.? without losing functionality
This is most likely done via the statuses and the Facebook-style Micropublisher modules. Note: there is a description of how to do integration with Statuses and Messages in this comment from issue 1751064
closed as duplicate, see #1969088: Changes to group browsing widget & user status updates