My thoughts were:

• Their forum must be really low volume if these spammings managed to get to the top
• UGC (User Generated Content) can easily put your website in a “bad light”, so you should be careful when using it.

Some ideas on how this could have been prevented:

• Provide an easy way for other users to flag messages as spam
• Only advertise on the first page topics which have at least one response and wasn’t flagged as potential spam.
• Use a list of keywords and quarantine posts which contain the given keywords: only show them to the IP address which originally posted it. Of course, such postings should be reviewed and innocent topics be removed from the quarantine status.

This last method leaves the spammer with the impression that the posting was successful. Directly blocking it would just create an arms-race. (This idea is not originally mine and it has been floating around on the intertubes for some time. It is surprising that so few community software packages implement it…)

• Full RSS feed to the site (so that it can be mined for malicious URL’s for research purposes :-))
• No-fluff interface
• When an external link is clicked, it first goes to a warning page

When it first launched it was criticized by some as an attempt to redirect traffic from CasleCops. Now that CastleCops is no more :-(, this shouldn’t be an issue. Hopefully the fact that it has some big companies backing it means that it’s not going anywhere soon (and that it can withstand any potential DDoS attack launched against it easily). The traffic is quite low at the moment (compared to some bigger forums), but probably it will increase. Finally, here is a short video presenting it (it focuses more on the UI side than the functionality):

PS. A revelation that came to me: how to repetitively execute searches on search engines without getting banned? (to find malicious links for example): you can Use their API, but you could also use Yahoo Pipes, which includes a Yahoo Search input module and you can get the results conveniently as an RSS feed, PHP structure or JSON (whichever is easier for you to parse).

• Flat discussion works best if few replies are expected for a given topic. You can make sure of this by splitting up the conversation by topic.
• Threaded discussion can be usable, but you must make sure that the user can keep track of the context. Two negative examples: the comments for Security Focus articles. More precisely: the way that the expand all link works (it shows a only a little bit of each post instead of showing the full text, making it unusable). An other problematic site: TechRepublic. Their biggest problem is that the post is placed at the top, without regard for its position in the tree. While this may eliminate some design problem, it completely breaks the association between the post and its context. Now a good example (IMHO): CodeProject. It uses javascript to load the message you request and display it in-line, keeping the context. When javascript is disabled, it uses server side scripting to imitate the same behavior (you can test this easily if you are using Firefox with the NoScript extension).
• For returning members it is very important to quickly find out what’s new. While the method of color-highlighting commonly used kinda works, the best way IMHO is to create an RSS feed for your forum.

And remember: software is not the solution, it’s just a tool. You can find articles and podcasts (part 2) about the human element which the most important factor in the community.