I was pointed to a site earlier, that provided nothing but links to malicious sites. Presumably the sites sole intention is for search engines to crawl it. What was interesting is it didn't have all of the links on one page - you had to keep refreshing it. Very boring and time consuming, so I wrote a program to do it for me.
Refreshing it 1000 times brought a list of over 800 unique sites involved. There's obviously very likely a plethora more. I'm working on getting them shut down as I write this, with hundreds of abuse reports being sent, but for clarity purposes, the sites involved are;
hpObserver details are at;
You'll notice there's a nice focus on some specific IPs, and the same is true with the registrars, with quite a few domains residing at a few specific registrars (nothing unusual, most malicious domains tend to be through specific registrars known for malicious activity).