Help me find this monetization method ...(Link in youtube description)

I noticed so many people on YouTube leaving some link (example: URL REMOVED) on their description.
It's some kind of ad display monetization method.
Can anyone tell? What it is?

Check the description of these videos-

https://www.youtube.com/watch?v=cKYHsv0mSlI&t=9s

https://www.youtube.com/watch?v=AfWdoWOA1fo

They are monetizing with adsense on their website. You will have to apply for approval

I don't understand what you're saying. What they are doing with their description field?

what is the role of fastproweb domain here?
Are they url shorting service




How the final domain - tech2edumac is monetizing from? Whose ads they run? is it google ads ?