[johnmorrison]

I feel like you're overestimating the differentiation and not accounting for the fact that 99% of the population basically just uses the minimal subset of features (sending plain text and images)

Two services don't need to have identical feature sets to interoperate, because you don't need perfect, full interoperability, if you can send most of your messages across platforms, that's still pretty good.

> Let me just make that last point clear: you cannot design a messaging protocol where one party sees emojis and the other doesn't.

Which service doesn't show emojis? Literally every mainstream mobile operating system and desktop browser supports emojis as regular text.

[jasonzemos]

> the fact that 99% of the population basically just uses the minimal subset of features

The tendency is for people to invoke features situationally. If you are communicating with someone who is using rich-replies there is a tendency to also invoke that feature yourself. If people are using emojicons there is a tendency for others to play along rather than use plaintext characters. Feature invocation is situational and relative.

> Two services don't need to have identical feature sets to interoperate, because you don't need perfect, full interoperability, if you can send most of your messages across platforms, that's still pretty good.

This has proven to result in an unacceptable user experience throughout the history of messaging. When a system loses social information from the environment it is no longer an effective communication tool. Worse, it is dangerous. If you send me a message and I respond to your message with some thumbs-up emoji, and your platform doesn't support it (e.g. a text-based IRC client) that information gets lost. You believe I have disregarded your message. You may assume I have been rude when the opposite is true. This is absolutely unacceptable UX.

[johnmorrison]

> This has proven to result in an unacceptable user experience... Worse, it is dangerous. If you send me a message and I respond to your message with some thumbs-up emoji, and your platform doesn't support it ... that information gets lost. You believe I have disregarded your message. You may assume I have been rude when the opposite is true. This is absolutely unacceptable UX.

This is an assumption that bad implementation is the only possible implementation, and it is wrong.

Obviously omitting content from missing features is bad UX - but it's absolutely not necessary to interoperate. It's easy (and should be expected) to avoid this by simply telling the user something from a missing feature has been sent - they can then inquire and get back the lost information / clear up the confusion.

Furthermore if interoperability is implemented on both ends, the sender's client should know to alert the sender before they attempt to use features missing on the receiver's end.

None of this is a difficult issue.