One thing that was disturbing me is that by default, in gnome bugzilla you won't receive an email notification if you, e.g. add a comment in a bugreport, or change the priority of a bugreport, because it's YOU who have done it.
Instead, in freedesktop bugzilla you will receive it by default.
I find it useful, because you can follow in your mailbox all the changes and contributions you have done in one evening and because it eases reading bugreports from email. Otherwise, if someone mentions you, you will have to go to the bugreport webpage to know what you said, because in the message thread for that bug, your comment won't appear.
Fortunately it was easy. It's enough going to "Preferences" and then "Email Preferences" and then uncheck all the checkboxes in the last row, which says "