I was trying to comment on this answer Is this how I tell whether or not I have "third party drivers"? and when I try to tag the user with "@" followed by their username, the rest of my comment posts, but the username and "@" vanishes. What's up with that?
User pings (
@USERNAME) in comments get automatically removed if you want to ping the author of the post (question or answer) below which you write your comment, unless that person or other users (not 100% sure about the exact rules) has already commented below their own post.
This is by design to avoid unnecessary
@USERNAMEs in comments, as the owner of the post you're commenting will always get notified anyway and it is not needed to indicate a dialogue flow as there is no dialogue before anybody else replied.