Any usenet group focused on a country in which bullfights occur may, at times have taurine-interest posts. You can also post TO the group here. As an alternative, you might try this Japanese archive of alt.culture.bullfight posts . It's a web site, so you should be able to connect to it with your browser. Mundo Taurino runs a handful of mailing lists through which taurine news and commentary are circulated.
Mail is distributed in Spanish, English, French, and Portuguese.
The mailing lists are not automated, and all mail passes through the webmaster's hands before distribution. Sign up through the link on their homepage. The list generates a handful of messages every day. This is to avoid conflicts between the members of the list and to respect all their points of view. The tone of list's messages is to be exclusively informative.