Brandenburg InternetWorking

dcrocker@bbiw.net

Semiotic Systems

rjbs@semiotic.systems

Applications and Real-Time reaction emoji social networking email affect messaging The popularity of social media has led to user comfort with easily signaling basic reactions to an author's posting, such as with a 'thumbs up' or 'smiley' graphic indication. This specification permits a similar facility for Internet Mail.

The popularity of social media has led to user comfort with easily signaling summary reactions to an author's posting, by marking basic emoji graphics, such as with a 'thumbs up', 'heart', or 'smiley' indication. Sometimes the permitted repertoire is constrained to a small set and sometimes a more extensive range of indicators is supported. This specification defines a similar facility for Internet Mail. While it is already possible to include symbols and graphics as part of an email reply's content, there has not been an established means of signalling the semantic substance that such data are to be taken as a summary 'reaction' to the original message. That is, a mechanism to identify symbols as specifically providing a summary reaction to the cited message, rather than merely being part of the free text in the body of a response. Such a structured use of the symbol(s) allows recipient MUAs to correlate this reaction to the original message and possibly to display the information distinctively. This facility defines a header field, to be used in junction with the In-Reply-To header field, to link one or more emojis as a summary reaction to a previous message. Unless provided here, terminology, architecture and specification used in this document are incorporated from , and . The ABNF rule Emoji-Seq is inherited from . Discussion of this specification should take place on the ietf-822@ietf.org mailing list.

A message sent as a reply MAY indicate the responder's summary reaction to the original message by including an In-Reply-React header field:

The for the header field is: in-reply-react = "In-Reply-React:" emoji *(lwsp emoji) CRLF emoji = emoji_sequence emoji_sequence = { defined in [Emoji-Seq] } base-emojis = thumbs-up / thumbs-down / grinning-face / frowning-face / crying-face thumbs-up = {U+1F44D} thumbs-down = {U+1F44E} grinning-face = {U+1F600} frowning-face = {U+2639} crying-face = {U+1F622}

The rule emoji_sequence is inherited from . It permits one or more bytes to form a single presentation image. The emoji(s) express a recipient's summary reaction to the specific message referenced by the accompanying In-Reply-To header field. . Fully interoperable email uses 7-bit ASCII, although some email handling paths directly support 8-bit data. Emoji characters are drawn from the space outside of 7-bit ASCII. For email handling paths that are 8-bit clean, the an emoji character does not need special encoding. If the path from author to recipients is not known to be 8-bit clean, The emoji character SHOULD be encoded using . Reference to unallocated code points SHOULD NOT be treated as an error; associated bytes SHOULD be processed using the system default method for denoting an unallocated or undisplayable code point. For recipient MUAs that do not support this mechanism, the header field might not be displayed to the recipient. To ensure that the reaction is presented to the recipient, the responding MUA MAY automatically include a second copy of the header field in the message body. This might be as the first line of the body or as the first mime-part. By making the text be the full header field, it also allows MUAs that do support the mechanism to identify this redundant information and possibly remove it from display.

This specification defines a mechanism for the structuring and carriage of information. It does not define any user-level details of use. However the design of the user-level mechanisms associated with this facility is paramount. This section discusses some issues to consider . Because an email environment is different from a typical social media platform, there are choices in the design of the user interface, to support indication of a reaction. Is the reaction to be sent only to the original author, or should it be sent to all recipients? Should the reaction always be sent in a discrete message containing only the reaction, or should the user also be able to include other message content? (Note that carriage of the reaction in a normal email message enables inclusion of this other content.) Reaction indications might be more useful when displayed in close visual proximity to the original message, rather than merely as part of an email response thread.

This specification defines a distinct location for specialized message content. Processing that handles the content differently from content in the message body might introduce vulnerabilities. However the mere definition or use of this mechanism does not create new vulnerabilities.

Add to "Permanent Message Header Field Registry": In-Reply-React Mail (RFC 2822) Experimental IETF This specification. None

Brandenburg InternetWorking THUS plc Google, Inc. Apple, Inc Qualcomm Incorporated Brandenburg InternetWorking University of Tennessee Innosoft First Virtual

This specification has been discussed in the ietf-822 mailing list. Active commentary and suggestions were offered by: Nathaniel Borenstein, Richard Clayton, Ned Freed, Bron Gondwana, Valdis Klētnieks, John Levine, Brandon Long, Keith Moore, Pete Resnick, Michael Richardson, Alessandro Vesely