If you want to bring someone else into a discussion or simply make it clear who you are responding to then you can use mentions.
You can refer to another user in the text of a contribution by using their username after an @ symbol, e.g. @johnsmith.
When entering a contribution, after typing @ and entering a first letter a popup will appear and the system will suggest matching users. If you keep typing the list of suggested users will be narrowed down. A user’s username is also shown on their profile.
The contribution containing the mention will be tagged with the user’s real name and the text of the mention will be linked to that user’s profile.
The mention will be added to the mentioned user’s Notifications activity stream on their radar, a browser notification will optionally appear and all the contributions they were mentioned in each day will be listed in the daily summary newsletter.