At least regular people have to sign in at registars, generally with a captcha, to see whois information, with no doubt IP numbers logged. Not so here, it's just all out there for anyone to see, to scrape - or whatever.
Of course, its a sign of "lack of quality" according to some, to have private registration, which would avoid this kind of indiscriminate disclosure, and I seriously resent this blatant publicizing of personal information, ostensibly facilitating invasive contact by anyone with internet access, regardless of their intent.
The "address" gained from whois is mostly pretty useless as a "locator" for a website; apart from the privacy issues this kind of service doesn't add any real value to the web.
I've never heard of an automated "wiki" being pumped out of databases before, and I think we can guarantee that if they didn't have internal access they would not be looking up each domain individually.
IMHO, it's a downright honeypot for linkpop and PageRank and is no better than scraper spam - if not worse.