Pro tip: clean YouTube links. When you get a link from YT, it includes an ID tracking back to YOU. It's a "query string" on the end of the URL like this:
...?si=[tracker_ID_here]
This ID allows YouTube (and their owner, Google, and *their* owner, Alphabet, and ALL of their associates) to track the people who click on the link, and the apps they used, back to you, building a network of none-of-their-business.
Good news: DELETE the "?si=..." part & the link works just fine without the tracking.
@VisualStuart There are also browser extensions to automate this, but... I'm given to understand that things can see what extensions you have installed and use that as part of fingerprinting, so it seems its advised to have as few installed as possible, so in the end I guess it's best just to manually edit the URL yourself.
As a side note, some sites have extra stuff in URLs they don't need anyway, so it's a good habit to have. For example, Amazon has a product code after the /dp/ but then they toss in a bunch of plaintext from the product title which their site doesn't really use but which makes for a long, ugly URL. Not tracking, just messy.