I was just thinking something along those lines. If you remove part of an ecosystem, the results can be unpredictable. BoingBoing readers come for the front page topics, but stay for the comments. They log on and begin to interact with the other commenters. If they read enough, they become regulars themselves. The regulars come to hang out in the Lounge, but also comment in the open forums. Many of the most prolific, smart and funny participants are in fact regulars, simply because they have found a place that suits them, and they account for a disproportionate percentage of the discussion on the BBS.
Take away any element, and the effects will ripple out through the system.