Ever since youtube has started, ads were a part of it. First around the videos, but later companies also started to sponsor channels directly. For review purposes, this is not so much a problem, but if every other video starts with "this is sponsored by raid shadow legends/nordVPN", then it starts to be annoying. Adblockers can only remove the surrounding ads, but the only option to remove the ads inside of the video is to skip that part, or stop the video entirely. SponsorBlock is a crazy strong add-on that will skip these parts for you. Thanks to the community based tagging, most videos that contain a sponsor are already blocked. This happens usually less than 5 minutes after the video is uploaded, so untagged videos are very rare. If the video isn't tagged, then it's very easy to help out other SponsorBlock users with the easy tool. All in all this add-on has made videos on youtube more to the point and far less annoying.