Hi Alesandro,
I don't know of any recent (or not-so-recent) changes to the moderation behavior - group members have always skipped the queue, as far as I know.
However, if you reply to an existing thread, your client will generally address the email as to: chromium-dev@ cc: [every other poster in the thread], and then even if your email is held for moderation, everyone on the CC line will still get it immediately. That can confuse people a great deal, since they will get replies from the people who got cced, but their actual post to the list itself is still sitting in the queue.
-- elly