How do comment @replies work?

Question

In a comment under my questions somebody used first name only @Ivoxzy instead of using the users full name @Ivoxyz FFlipse

Is the correct user going to informed about this message that was address to him/her?

Answer 1

@Ivoxzy instead of using the users full name @Ivoxyz FFlipse

Yes. Why? These are rules for comment @replies to work:

^{stolen from MSO answer}

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You can use @name syntax anywhere in your comment to reply to a specific user. This will notify that user in their global inbox. There is no notification through email.

In short:

• See comment replies in the Markdown help.

Some more detail:

• The first author of the question or answer will always be notified of any new comment.
• You can explicitly notify one (1) other commenter or editor, by using @name, where name is the username with all spaces removed.
• Single trailing punctuation such as a dot, comma or colon is ignored, like @name, yes works, but @name... no does not.
• Things like @op, @downvoter or @all have no special meaning.
• If a user comments on their own post and there is only one person who has previously commented, then that person is also notified if @name is forgotten.

And all details that make this work:

1. Notifications apply to the author, commenters, and editors of the question or answer that you are commenting on—users not in that list cannot be notified. You can also notify a ♦ moderator who closed the question. The question and answers are all considered independently. For example, if Alice was the author of, commented on, or edited the question or her answer, then you cannot notify her by commenting on Bob's answer (unless Alice also participated in that answer), and vice versa.

2. You must include @name, where name is a reasonable match to a user's current display name. Users who have not set a display name in their profile are not notified.

3. If the first word in the display name is at least three characters long, then there must be a starts-with, case-insensitive match of at least three characters in the display name. This means @a and @ab will never match anyone, unless a user uses a first word that is only two characters. Like: @Jo will notify Jo Miller, but not John, and @B. will notify B. Gates, but not B.Gates. Users with a display name of just one or two characters are unnotifiable. If there are more than three characters in @name, then all given characters must match (neither @alix nor @aliceinwonderland will match user Alice).

4. Matching is performed in reverse chronological order, so if five people named John are participating, @john will match the most recent John. (Use the next rule to differentiate.)

5. Spaces are removed from the display names for matching purposes. So to match Peter Smith you may use @pet, @peter, @peters, or @petersmith. The last two are useful if Peter Jones is also participating, who can then be distinguished using @peterj. However, no spaces are allowed in the @name itself. Like to notify P Smith, one must use @psm or @psmith. (Here @P Smith would be handled as just @P, which is too short.) Single quotes, dots, dashes and underscores should not be removed.

6. Special characters are replaced with their simple equivalent. To reply to Piëre you can use both @piëre and @piere. And to reply to Jörg you could use @jorg, but not @joerg.

7. Comments containing more than one @name are blocked unless they contain a backtick `. In the latter case, only the first name mentioned using the @name syntax will be notified. For example, @alice @bob Hi!` will notify Alice (if she has participated in that post), but not Bob.

8. An exception is the case when the first @name either matched nobody, or matched the post's author (and thus isn't necessary); in this case, the next @name will be checked.

9. When editing a comment within its limited editing period, if you change or add @name, the notification may or may not reach the new recipient depending on timing.

10. The first author of the question or answer will always be notified of any new comment. There is no need to use @name to notify them. (You may still use it for clarity, if needed; however if only you and the author have been commenting on the post so far, the @name will be automatically removed from the beginning of the comment, as it adds no value.)

11. The notification must begin with a space or be at the start of the comment. For example, you cannot use markup such as italics.

12. Single trailing punctuation such as a dot, comma or colon is ignored. Like @name, yes works, but @name... no does not. (Though a dot is valid in a username, the last dot is removed for matching, so @St will notify St. although only two characters are used.)

13. The notification only works for the username that is current at the time the comment is submitted, not any previous username(s) the target may have had.

The exact matching rules are not documented, but extensive tests performed on 30 August 2011 indicate that the following algorithm is used:

• Take the first word immediately following the @, where the word boundary is determined by a space, a character not valid in user names (such as : , / ! ?) or the end of the comment.
• Remove one trailing dot . from the resulting string if applicable (and if the string has more than two characters).
• If the remaining string ends in ' or 's, remove that piece from the string.
• The resulting string will be matched against the user name with spaces removed.

Example: The comment ends with @O'Conner's.). The word immediately following the @ is O'Conner's. since ' and . are valid in user names. Then the trailing dot is removed, and finally the 's is removed, resulting in O'Conner.

Some examples of supported notifications:

• @name some text
• @name: some text
• @name. Some text
• @name, some text
• some text, @name
• some text, @name, more text
• Some text, @name.
• This is mentioned in @name's comment.
• @P. for both P. Smith and P. Jones (whoever commented most recently), but not P.Smith nor P.Jones. Likewise, @P. Smith is handled as @P., so also matches P. Smith or P. Jones.
• @psm or @psmith for P Smith
• @peters or @peterj for Peter Smith or Peter Jones respectively

Examples that will not trigger notifications:

• @name...
• abc@name
• *@name*
• *@name:*
• [@name](http://some-url)
• @[name](http://some-url)
• @P Smith