So many other ways to handle it then screening posts. Here are a few methods broken down into different trains of thought.
First, they could focus on the poster/s. I suspect its one group, if not just one poster. A simple IP ban would probably be enough to make them move on. Or they could actually track them down and launch a complaint with their ISP.
Second, they could go after their ability to make fake accounts. Put some kind of cryptic or other human-only method of making a account. How about making a email confirmation system? Or confirmation of one of their products Serial Numbers? Or just monitor where they new accounts are coming by by tagging a time, IP, and general area. If a Sysop sees 500 accounts suddenly spring out of some town in China, that should be a red flag.
Third, they could control the posts. Make it so you could only make 10 posts a day. Or better yet, make it proportionate to how long you have been a poster, and how many total posts you have. A rank 1 could only make 3 posts a day, but anything about a rank 5 could make a unlimited amount. Those numbers could be tweaked ofcourse. Another thought is they could make it so you can reply as much as you want, but could only create a topic after 20 such replies. Or we could incorporate some sort of Kudos system, where you would need 3 kudos to make a new post. Another idea is to ask certain high ranking posters to be Moderators. I mean they have already taken the burden of D-links responsibility, how about granting them some power to better their cyber community? Most of these systems are already used in other boards, and those are just for hobbies. Come on Dlink, this board actually supports your products. Not only does this forum save your money in call volume, but its a space your could advertise your products and even other people's products. There is advertising space everywhere. Granted, I hate ads, but I hate being totally ignored even more.
Damn, I didn't mean for that to come off as a rant. But those are some decent methods to control spammers. And there mostly cheap, if not free. Online self help support is the wave of the future, and this is core of that community.