trelloでBoard全体の変更をメール通知
ちょっと迷ったので。
Subscribing to a board
Click the board title or the "Options" menu on the right and choose "Subscribe." This will notify you of changes to all cards in that board.
Trello Help | Subscribing to cards, lists, and boards
Boardを表示して、ページ右側のOptions > Subscribeを選択。