A last missing link for interoperable representation

[James Kass via Unicode]

Not a twitter user, don't know how popular the practice is, but here's a 
couple of links concerned with how to use bold or italics in Twitter 
plain text messages.

https://www.simplehelp.net/2018/03/13/how-to-use-bold-and-italicized-text-on-twitter/
https://mothereff.in/twitalics

Both pages include a form of caveat.  But the caveat isn't about the 
intended use of the math alphanumerics.

The first page includes the following text as part of a "tweet":
Just because you ������ doesn’t mean you ������������ :)

And, as before, I have no idea how /popular/ the practice is.  But 
here's some more links:

(web page from 2013)
How To Write In Italics, Tweet Backwards And Use Lots Of Different ...
https://www.adweek.com/digital/twitter-font-italics-backwards/

(This is copy/pasted *as-is* from the web page to plain-text)
Bold and Italic Unicode Text Tool - �������� ������ �������������� - YayText
https://yaytext.com/bold-italic/
Super cool unicode text magic. Write �������� and/or ������������ 
updates on Facebook, Twitter, and elsewhere. Bold (serif) preview copy 
tweet.

Michael Maurino [emoji redacted-JK] on Twitter: "Can I make italics on 
twitter? 'cause ...
https://twitter.com/iron_stylus/status/281991180064022528?lang=en

Charlie Brooker on Twitter: "How do you do italics on this thing again?"
https://twitter.com/charltonbrooker/status/484623185862983680?lang=en

How to make your Facebook and Twitter text bold or italic, and other ...
https://boingboing.net/2016/04/10/yaytext-unicode-text-styling.html
Apr 10, 2016 - For years I've been using the Panix Unicode Text 
Converter to create ironic, weird or simply annoying text effects for 
use on Twitter, Facebook ...

How to change your Twitter font | Digital Trends
https://www.digitaltrends.com/.../now-you-can-use-bold-italics-and-other-fancy-fonts-...
Aug 14, 2013 - now you can use bold italics and other fancy fonts on 
twitter isaac ... or phrase into your Twitter text box, and there you 
have it: fancy tweets.

Twitter Fonts Generator (�������� ������ ����������) ― LingoJam
https://lingojam.com/TwitterFonts
You might have noticed that some users on Twitter are able to change the 
font ... them to seemingly make their tweet font bold, italic, or just 
completely different.