I just want to know -
does that technique even work? I can't imagine anybody clicking or doing anything with something so ridiculous.
Yup
There are softwares that will scrape the internet looking for forums that are spammable (if thats even a word). It will auto-register username and passwords and spam the sh!t out of hundred of thousands of forums.
You do get clicks but more importantly you have tens of thousands of domains pointing back to your URL. Thats important because that significantly improves seo ranking in Google.
Backlinks are king
Also dont underestimate the stupidity of people. You'd think it be common sense not to click blatant spam thats in your email but people do it every day.