FTC said that creators and influencers on social media services need to put "sponsored", "promoted" or "ad" tag disclosure on brands they are endorsing so it would be possibly for someone to make uBlock Origin filter which blocks such content.

The sponsor block extension is crowd funded, people put where the sponsor message is and it automatically skips it. Not sure if ublock can seek inside a youtube video.

>Not sure if ublock can seek inside a youtube video.

I was referring to a hashtag or simply a tag a piece of text that can be spotted and then that type of content skipped.

In videos with sponsors, YouTube adds a small notice when the video starts that says the video has sponsored content. It doesn't tell you where/when.

For example take a look at this sponsored video: https://www.youtube.com/watch?v=AkcWQO57bGk

YouTube adds an overlay* in the upper left corner which says "Includes paid promotion". The overlay leads to https://support.google.com/youtube/answer/10588440

Also creator added "#sponosred" hashtag.

Both "Includes paid promotion" overlay* and "#sponsored" hashtag can be detected and therefore the video could've been skipped or hidden by some extension or by uBlock Origin filter. You can either rely on detecting aforementioned Google overlay* or sponsored hashtag.

*HTML code of "Includes paid promotion" overlay:

<div class="ytp-paid-content-overlay" aria-live="assertive" aria-atomic="true" data-layer="4"><a class="ytp-paid-content-overlay-link" target="_blank" style="display: none;" href="https://support.google.com/youtube?p=ppp&amp;nohelpkit=1"><d... class="ytp-paid-content-overlay-icon"><svg fill="none" height="100%" viewBox="0 0 24 24" width="100%"><path d="M6 9H5V5V4H6H19V5H6V9ZM21.72 16.04C21.56 16.8 21.15 17.5 20.55 18.05C20.47 18.13 18.42 20.01 14.03 20.01C13.85 20.01 13.67 20.01 13.48 20C11.3 19.92 8.51 19.23 5.4 18H2V10H5H6H7V6H21V13H16.72C16.37 13.59 15.74 14 15 14H12.7C13.01 14.46 13.56 15 14.5 15H15.02C16.07 15 17.1 14.64 17.92 13.98C18.82 13.26 20.03 13.22 20.91 13.84C21.58 14.32 21.9 15.19 21.72 16.04ZM15 10C15 9.45 14.55 9 14 9C13.45 9 13 9.45 13 10H15ZM20 11C19.45 11 19 11.45 19 12H20V11ZM19 7C19 7.55 19.45 8 20 8V7H19ZM8 8C8.55 8 9 7.55 9 7H8V8ZM8 10H12C12 8.9 12.9 8 14 8C15.1 8 16 8.9 16 10V10.28C16.59 10.63 17 11.26 17 12H18C18 10.9 18.9 10 20 10V9C18.9 9 18 8.1 18 7H10C10 8.1 9.1 9 8 9V10ZM5 13.5V11H3V17H5V13.5ZM20.33 14.66C19.81 14.29 19.1 14.31 18.6 14.71C17.55 15.56 16.29 16 15.02 16H14.5C12.62 16 11.67 14.46 11.43 13.64L11.24 13H15C15.55 13 16 12.55 16 12C16 11.45 15.55 11 15 11H6V13.5V17.16C8.9 18.29 11.5 18.93 13.52 19C17.85 19.15 19.85 17.34 19.87 17.32C20.33 16.9 20.62 16.4 20.74 15.84C20.84 15.37 20.68 14.91 20.33 14.66Z" fill="white"></path></svg></div><div class="ytp-paid-content-overlay-text">Includes paid promotion</div><div class="ytp-paid-content-overlay-chevron"><svg height="100%" version="1.1" viewBox="0 0 32 32" width="100%"><path d="m 12.59,20.34 4.58,-4.59 -4.58,-4.59 1.41,-1.41 6,6 -6,6 z" fill="#fff"></path></svg></div></a></div>

sponsor block skips the part where the speaker is talking about a sponsored product/service

But if the video is sponsored then the whole video is about a sponsored product/service.

I'm curious about how sponsorblock works - how does it prevent malicious users from submitting fake segments to skip?

It needs multiple people to submit similar segments, before it starts blocking the segment for everybody else.