When you share a YouTube video using the share button it adds “si=some_unique_code” to the URL. If you don’t remove that it shows your personal account to anyone who receives it so that they can chat directly with you. For a lot of people this is their real name.
I’ve seen it all over Lemmy so I figured I’d mention it here! You only need the stuff before the question mark in the URL to let others see the video.
This can also be turned off in your YouTube settings under the privacy section. The setting is “channel visibility for shared links”. It will still add the si code for tracking though.
Yeah, it’s easily possible to set it up to save the original link somewhere hidden. Same reason why you shouldn’t reuse passwords because it’s trivial to set up a site to look like it’s doing it right from the outside but actually saves all passwords in plaintext for owners, admins, or disgruntled staff to look at later and see if it logs in to your email.