We have developed initial functionality for @mentions of people via OpenLab. Given that notifications are controlled at the group level for every group, @mentions are not needed for notification, but are a useful way to track and highlight when you are directing a comment at someone. Importantly, the name name to use should be the same as their profile name. Eg. My mention tag is @rishabh and my profile is at:
As we build the app, @mentioning people will be an integral way to associate posts with people other than the person who created the post. As we learn more about your needs, we will make this feature as useful as possible to you.