Source identifiers are used to track your activity on a website..

Where you came from, what device you use, and even who you talk to.

Whether it's written clearly in the url or tied to a random string of characters, it's assigned to your activity.

When you send a link containing a source identifier to somebody and they click it, it signals to the website that you two are connected.

And that data goes right back to the website operators, and thus their advertisers.

Whenever you select "share" or "copy link" on a social app or website, it creates a link like this.

If you give even the smallest shit about online privacy, it's important to remove them.

Everything after the "?" symbol can be removed without issue, especially sections starting with "si=" or "utm _source=".