# The @ symbol, does this do anything or are people just using it to reference a person because of Twitter?

I get a lot of @MarkLaPolla but I have not noticed any special notification. I get notification with or without the use of the '@'. If the '@' is special, how do I use it to send notifications. Thanks.

• The use of @ to refer to a specific person dates back to IRC at least, long before Twitter – Carl Mummert Oct 15 '15 at 0:56
• Search for other meta questions with the "notification" tag to find previous discussion of the ways in which the at-sign works (and doesn't work). – Gerry Myerson Oct 15 '15 at 1:51
• Your assumption that Twitter must have been the first to use the "at" symbol as ... well ... an "at" symbol ... reminds me of these (hopefully satirical) questions that pop up now and again on Yahoo and Quora: answers.yahoo.com/question/index?qid=20140620211110AAdYlIk "I found a 90's phone that has a hashtag button on it. Twitter wasn't even invented yet so why did they need hashtag buttons???" – Marcel Besixdouze Oct 15 '15 at 3:08
• Maybe reading the links given here might help. If you mean using of @username in chat , and not in comments, you should clarify this in the question. (And add (chat) tag.) – Martin Sleziak Oct 15 '15 at 10:19
• Re: I have not noticed any special notification; Try checking this link or clicking on the inbox icon to make sure whether the responses you mention did not get into your inbox.. – Martin Sleziak Oct 15 '15 at 10:25
• @Marcel: That is pure gold. – Asaf Karagila Oct 15 '15 at 12:05
• My assumption was you mathematicians wouldn't know about IRC, TCP or the like so I picked one of the most popular use of the '@' symbol right now, besides, mail that is. Also since I wasn't sure how old anyone was on this site. :-) Not that I'm calling anyone old. I made no assumption that Twitter used the @ symbol first. ;-) However, @Marcel, I haven't noticed a difference in notification. Oh, and twitter started out using SMS. I founded a company that used SMS as a user to user messaging. It was originally used as a switch to switch operator communications system, if I remember correctly. – Mark LaPolla Oct 15 '15 at 14:44
• @Marcel that IS pure gold. LOL. :-) Thanks for that. – Mark LaPolla Oct 15 '15 at 14:54

To complement robjohn's good answer let me just add that not rarely when it is used in fact it does not do anything as user use it in ways so that it will not result in a notification (or indeed will be redundant as you remarked). Very roughly, it can be used only to reply to users already in a communication not to call somebody into a communication. Furthermore the owner of a post is always notified of a comment as well as a unique commenter in a conversation with the own of the posts. Details are at

How do comment @replies work?

• Ah, ha! I thought so. Thanks. Just wanted to make sure. – Mark LaPolla Oct 15 '15 at 14:47

In chat, the '@' symbol signals type-ahead for names and usually makes an audible ping on the recipient's computer as well as leaving a message in their inbox (the blue inbox icon next to "StackExchange").

In comments, the '@' symbol signals type-ahead for names and leaves a message in the recipient's inbox