This is my first post on thew new SCN, and I'm trying to tag some of the users that I have been following using '@user_name'. But it's not really picking any suggestions nor tagging the user? Has something changes in terms of tagging the users?
The functionality you are referring to is known as "@mentioning". The @mention feature is in the process of being developed for SAP Community. You'll find it in the list of upcoming improvements discussed by Gali Kling Schneider in her post Mapping the Journey Ahead..