It's a community of people who suggest sections of video to skip for they are paid speech and other irritant such as interaction reminders, and other indesirable things, it also includes labelling, such as tangents which some people might want to also skip.
I think it is a natural part of us wanting to reclaim our attention back.
https://sponsor.ajay.app/
https://github.com/ajayyy/SponsorBlock
https://addons.mozilla.org/en-GB/firefox/addon/sponsorblock/
https://chromewebstore.google.com/detail/sponsorblock-for-youtube/
It's an addon and we the viewers crowdsource the labelling for the people who come after us
I don't know who ajay is but thank you ajay