If there is some way he could be found liable for statements made on a messageboard he controls (and I could only find opinions to the contrary in my cursory review of case law), it certainly isn't through the provisions of the DMCA. I'd be really interested to know what cases you think hold otherwise.
As I said earlier in this thread, the DMCA applies to copyright. But it also defines a distinction between an ISP and an editorial publication. That distinction is being used, without reference to the DMCA in other cases, and in particular defamation cases.
I can't tell you court cases as I am not a lawyer. I can only relay what my council tells me. I'm in the internet business and in particular the content business so I try to keep up to speed on details such as these.
If you want the name of a good California based new media attorney who is up to speed on all of this, I can PM the info to you.
AmbergrisCaye.com 
