The correct way to report GNU Emacs bugs is by e-mail to firstname.lastname@example.org. Anything sent here also appears in the newsgroup gnu.emacs.bug, but please use e-mail instead of news to submit the bug report. This way a reliable return address is available so you can be contacted for further details.
Sending bug reports to help-gnu-emacs (which has the effect of posting on gnu.emacs.help) is undesirable because it takes the time of an unnecessarily large group of people, most of whom are just users and have no idea how to fix these problem. bug-gnu-emacs reaches a much smaller group of people who are more likely to know what to do and have expressed a wish to receive more messages about Emacs than the others.
However, RMS says there are circumstances when it is okay to post to gnu.emacs.help:
If you have reported a bug and you don't hear about a possible fix, then after a suitable delay (such as a week) it is okay to post on gnu.emacs.help asking if anyone can help you.
If you are unsure whether you have a bug, RMS describes how to tell:
... if Emacs crashes, that is a bug. If Emacs gets compilation errors while building, that is a bug. If Emacs crashes while building, that is a bug. If Lisp code does not do what the documentation says it does, that is a bug.