I asked our IP attorney about this today. According to him, the ruling I referenced established legal precedent that forum owners are essentially liable for trademark infringement in the same manner as covered by the DMCA. This apparently occurred through the ruling establishing a similarity relationship between the DMCA and trademark rights. Even though eBay won the case, the reason they did was because, when notified about the counterfeit goods, they took action to remove those listings. Apparently, this ruling had major implications.
This is not the kind of thing I would say to a non-lawyer, because of the potential for confusion. What you need to understand is that primary liability needs to arise before any possibility of vicarious/contributory/secondary liability can arise. A bulletin board operator can't be liable for TM infringement through people engaged in normal discussion on its forae, because that discussion cannot give rise to primary liability.
Conversely, if people are offering fake Rolexes for sale on my commercial website (Ebay - note that Ebay makes money off the sales), and I have good reason to think they're fake, and I allow this to continue, then I can be held liable. This arises from the normal operation of TM law, nothing to do with the DMCA though. If there's a point re the DMCA it's that take-down upon notice should prevent liability, just as the DMCA protects OSPs from liability if they take-down upon notice.