@UserName in ArcGIS Online Item Comment

[Anonymous User]

ArcGIS Online is the Authoritative location to find your organization's geospatial content, and it's the perfect spot to collaborate over information and information products.  Currently, to collaborate over the creation or use of an information product, I'd need to communicate using a separate medium:  email, calling or some additional measure.  I'd like the ability to be able to communicate with another user by utilizing the comments section.  I'd like to address a user by typing '@' in comments, and have a list of user names show up so I can decide who I'm 'speaking' to.  Additionally, this will trigger AGOL to email the user my comment. 

Incidentally, when I type '@' here, GeoNet knows to exhibit this pattern

Thanks!