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.
As a web developer, everything after the ? is actually parameters for the request. Anything could be in there, even important stuff (though hopefully nothing identifying, since that is extremely unsecure). You will likely break functionality if you delete everything without knowing what it is.
Usually parameters are easy to understand. Like the time parameter in yt URLs, which is t=180 (meaning 180 seconds from the beginning of the video). Usually, parameters that are a string of seemingly random letters are UIDs or tracking parameters. Whenever I see a URL with one or multiple of those, I start deleting them and seeing if the URL still works. In 90% of the cases, it still does. Amazon is one of the worst offenders, with usually 4 or 5 random looking parameters that can be deleted without affecting the functionality of the URL.