QuakeML Mailing List
There is a public mailing list for QuakeML, which is open to everyone, at firstname.lastname@example.org. You are welcome to sign up on the web. Alternatively, send an empty e-mail (remove signature in mail body) with the subject line "subscribe quakeml <YourFirstname> <YourLastname>" to sympa(at)sympa.ethz.ch (please fill in your first and last name accordingly).
Note that you can only post to the list if you go through the sign-up and approval process beforehand.