Parasite Hosting Questions

So I'm trying to learn more about parasite hosting, seen tidbits here and there.

My question is in regards to using redirect pages on high authority sites.

Let's say I find a site and my link looks like this


Now I assume all i need to do is promote that link on the web so it gets spidered and then google indexes that page(or the redirect page?)? How does parasite hosting with redirects links like that work?


Or take for instance this listing i get when I type in "buy viagra online" in google


How are the spammers generating that html file on that server so it will redirect to the page? If I get that down I'm golden! I got a great focused niche and would love to see the traffic I could get from this.
Thanks!

or take another example this guy. for the keyword "buy cialis" which was indexed just 23 hours ago and is showing front page!

How the heck does one generate that! Looking forward to the responses.

he hacked the sites and uploaded a bunch of autogen pages and its using js to redirect based on referer.

yeah I did some research, I guess its all XSS exploits. Funny I found several prestigiuos .edu domains that are wide open to SQL injection exploits. But I dont think I can cross that line and take advantage of it. Too illegal for me.

Although I did lawl when I did a hi' or 1=1-- on a prestiguoes university login page and got right in. Thank god for public wifi.