The domain for that site is owned by a Chinese university, and the IP address of the server it's hosted on looks like a shared server (there's over 200 sites hosted on that IP). I doubt Mark has anything to do with hosting that site.

Out of sheer curiosity - how do you tell how many sites (and which ones) are hosted on a shared server?

http://spyonweb.com/

  or

http://w3who.net/

They are not always 100% complete, but they are free and have good coverage.

For example, did you know that ycombinator.com also hosts workatastartup.org? http://spyonweb.com/ycombinator.com

You look up the DNS server: http://network-tools.com/default.asp?prog=dnsrec&host=di...

Then a whois record on the DNS: http://whois.domaintools.com/domaincontrol.com

Then a quick Google search shows results like "Note that anything ending in domaincontrol.com or secureserver.net is hosted by godaddy.com and/or wildwestdomains.com! If you have webmail, you can ..."

Another good method is to get the sites IP address (`nslookup` or `dig` are good tools for this. Hell, `ping` will do it for you too). Then head over to bing.com and search for ip:addr.

For example: http://www.bing.com/search?q=ip:174.132.225.106

I'm not sure the .com is canonical. I don't speak Chineese so I don't really know what is going on with that site. the .org variant and his other pages are all returning 410 Gone.

Mark Pilgrim's website is diveintohtml5.org. If you compare WHOIS information, it is clear that diveintohtml5.com is owned by Xiaokang Liu, not Mark Pilgrim.

I noticed this earlier, but it seems he doesn't actually run the http://diveintohtml5.com, according to a whois search. As macrael pointed out, the rest of the .org variants are gone.