QuakeML Mailing List
There is a public mailing list for QuakeML, which is open to everyone, at quakeml@sympa.ethz.ch. 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 Firstname Lastname" to sympa(at)sympa.ethz.ch.
Note that you can only post to the list if you go through the sign-up and approval process beforehand.