The latest version of LISTSERV(R)  1.8d already has an online interface
to many common commands, both from  list-owner and subcriber perspectives.

Furthermore, posting (NOT using email) can be done online via that HTTP
interface.

Finally, this version supports RFC822 header only subscrption e.g.,

mailto:[log in to unmask]

i.e, no SUBJECT: or body-of-text required.

With a receiver's compliant mail user agent, you may generate
body-of-text commands by using the <per-cent>20 as a single blank.

mailto:[log in to unmask]