Actually, The Holders and our current mass edit are slightly related. The Holders were a creepypasta series following a basic format, somewhat like the SCP. The basic structure was this: go to unsettling place —> find a creepy person —> experience/do/have a unsettling event —> acquire a item from the creepy person (holder) which will cause BAD things if all the items are brought together. All of this was accomplished with great deal of descriptive and creepy text, and the overhanging threat of intensely unpleasant death for even the slightest mistake.
The issue that came about was this: The Holders were the work of primarily one man, and he lost his frigging mind. He started posting, stating that this was all real, and that he was finding the items. I honestly don't know how it all ended, as I tuned out around the time he started to mention god-like power and dismissing other people's contributions as "silly fiction".
The wiki has allowed us to largely avoid any one person freaking out and polluting the whole work. However, it's also allowed for a lot of contributions to be added that, while interesting, are just not that great. The mass edit is (hopefully) intended to weed out items that don't fit, make room for new and better content, and generally increase the overall quality of the work.
I have to agree with the wiki-walk statement as well. If nothing else, the SCP are good for eating up time at a abnormal pace. Every time someone says they've lost three hours just browsing around, it makes me grin. The new site has been running for over a year now, and i'm hoping to keep it going for many more. Heck, we even have a "Aperture Science"-style site in the works...