YSK: that you can YouTube videos without being intrurpted by adverts. If you skip the video to the end, hit the replay button that should restart the video without any adverts.
from /r/YouShouldKnow
YSK：你可以在不被廣告侵擾的情況下觀看YouTube視頻。如果你跳過視頻到最後，點擊重播按鈕，應該重新啓動視頻，沒有任何廣告。