Have you ever run into a video that has been broken up into chapters? If so, the person who uploaded that video knew how to add timestamps on YouTube properly. Timestamping on YouTube was always an important way of getting people to watch a certain area of a video. Over time, the feature grew to allow users to divide up videos, add reference timestamps in comments, and even send people URL links that will link directly to that timestamp in the video.
Read more: How to speed up (or slow down) YouTube videos