Perry E. Metzger explains why he does not allow HTML email to be sent in the cryptography mailing list. I copy-and-paste:

1. Many people still read their email in systems that handle only plain text effectively. They’re a large enough group that I don’t like disenfranchising them.
2. HTML email, like most machine parsable data, often has “gotchas”, and as this is a security oriented list, I really don’t want to have to vet email for hacking attempts. Vetting real code is unpleasant enough — I don’t want to have to look for attempted buffer overflows and web bugs in email I’m forwarding.
3. HTML email is harder to search, to edit down, to cut and paste cleanly, etc.
4. HTML email is often just plain ugly to look at.

To those who often without previously thinking thoroughly their suggestion and only judging by their own limited experience, propose that he should simply switch his email reader to a GUI one, he responds:

I’m one of the group that reads email in a non-GUI. Please don’t tell me to switch mail readers, because I’ve yet to find a GUI based one that will let me process hundreds to thousands of incoming emails a day efficiently, and without efficiency I’d stop getting any work done. Pretty toys are great if you’re reading 20 messages a day and can’t remember commands — I need stuff that’s fully programmable.)

Haven’t I been told to switch my MUA on numerous occasions! For many many years I even silently refused to accept .doc attachments or worse winmail.dat ones. Why on earth would one fire up Word to write three lines of plaintext?

Oh well, now with alpine’s prospects uncertain, it may be time to check whether sup is a suitable MUA (mail user agent) for me.

[via cryptography]