You buy domains and then you change some settings on your provider of your domain and then submit the link in your control panel on Adsense that basically gives Google control of domain, and then they will do this to your domains:
These are my parked domains. But, it doesn't "give" the domain to google, just gives them permission to put ads on, and you can get it back at any time.
I never clicked mine. I think it was because one of members was clicking them like 15 times a day. he thought he was helping but I kept telling him no to do it.
I guess that is a way to get someone elses account suspended if you want. Lol.
I had a total of $75 as of yesterday. But google disabled my account for invalid clicks, which is absurd because I've never clicked my own ads or asked people to. 4 months of google for nothing. Can't believe this.