That site is way off. I am 110% certain I have a dedicated server and know which sites are on which IP. I just did a search on one of my domains and the results included both the domian.com and
www.domain.com version of my site on that dedicated IP, as well as a site I've never heard of.
I did a whois on the site I've never heard of and the IP it is actually on is NOWHERE near mine.