[wvenable]

I was expecting something significantly different from HTML but this is really just pre-CSS HTML with different tags. At this point, I can't imagine another SGML based language for formatting is necessary.

If everyone could just agree on a safe subset of HTML for email then that's all we would need.

[jcranmer]

Thunderbird literally implements it by rewriting it into HTML: https://dxr.mozilla.org/comm-central/source/mailnews/mime/sr...

text/enriched was basically proposed as an interim result for richer text than plain text back when HTML email was controversial.

There is a more-or-less defunct community group at the W3C about building an HTML email specification. In practice, the elephant in the room remains Outlook, which uses the same HTML engine built into MS Word, which, IIRC, is built on IE 5.5.

[TazeTSchnitzel]

Unlike HTML, the the syntax is minimal and trivial to parse (there's no attributes or implicitly-closed tags, and there's only a single character entity (<<)), and it's limited to a very small set of clearly-defined formatting options.

In lacking most of HTML's complexity and features, it lacks its security issues, too. And in being very small, you can reasonably expect the whole spec to be implemented.

But yes, with a very strictly validated, very small HTML subset you could get a similar effect. At that point, though, why use HTML?