You can also remove yourself from the mailing list, and still post to the
forum from the web. I made that change when the multiple spam posts problem
started, so thats what I do now. I think the forum and mailing list shouldn't
be linked by default, only if you opt-in at signup.
I also believe this issue is a lot broader than just this problem. I've
always thought this forum, attached to the Trisquel web site, is too small
and restrictive. Trisquel users (and maybe all free software OS users) need a
new bigger, more scalable forum, for example, PhpBB or BBPress. That would
solve a lot of problems in one.... the spam posts, the email addresses
showing, the mailing list (users can choose the mail notification they want)
etc ...
There's many possible ways to do this.... for example, all the FSF approved
GNU/Linux distros could get together and Trisquel could be one forum within a
larger FSF GNU/Linux forum board. Or there could be a separate Trisquel user
forum linked to the main Trisquel website.