youtube timestamps extension looks at the comments with timestamps and adds a little white bar on the timeline that lets you see when someone commented. This is useful when watching to see moments people react to.
Recently i've been learning how to swim. It's been going quite well actually every week I improve a little bit. Yesterday I was able to do 50m freestyle without feeling like I was going to die, and also managed to do a 25m min breath % of 2 breaths!
On a swimming tutorial video, you'll see some comments spread throughout the timeline, but a strange cluster all a the 1-3m mark. This is because many people like to post their average 100m times in their comments, and the extension plots them together on the timeline for us to look at. From video to video you can see how different commenters swim, or are aiming to swim like, and how they cluster and move around. Thank you internet!