What are appropriate messages for the various Emacs newsgroups?
The file etc/MAILINGLISTS describes the purpose of each GNU mailing list (see Informational files for Emacs). For those lists which are gatewayed with newsgroups, it lists both the newsgroup name and the mailing list address. The Emacs mailing lists are also described at the Emacs Savannah page. The newsgroup news:comp.emacs is for discussion of Emacs programs in general. The newsgroup news:gnu.emacs.help is specifically for GNU Emacs. It therefore makes no sense to cross-post to both groups, since only one can be appropriate to any question.