I'm not entirely clear whether BATMAN: YEAR ONE was an Elseworlds type story, or a full-fledged reboot. I don't recall it being rigidly held continuity in subsequent issues, but maybe it was.
Year One was considered fully "in continuity" when first published, but DC later backtracked a little on some of the more controversial aspects (Selina as an S&M hooker for example) and (I think) used "Zero Hour" to take those apsects out of continuity.
