[ergothus]

You can also assume that copy will remain readable - standards and multiple vendors matter.

I have no huge issue with moving to a more IM-based interaction as my default, but I've yet to find one that is actually compatible with them all. I need 3-5 apps to communicate to everyone right now, and in a few years some of those will be gone and new ones will be added.

[ams6110]

This is part of why I send email in plain text. HTML is probably not going away any time soon, but plain text has been around several decades longer at least.

[ryandrake]

At least HTML can be trivially converted to text. Who wants to bet that your conversations in WhatsApp, or WeChat, or Facebook, or whatever the kids are using today, are binary blobs that require a running, proprietary "app" to view, or only available through a cloud service?