Noticeboards are multiplying on en.wikipedia faster than I can count. There's the admin noticeboard, the incidents subpage, the 3RR subpage, the ArbCom enforcement noticeboard, the community sanction noticeboard, six sections of the Village Pump, a noticeboard or two for many WikiProjects, in addition to the WikiProject's talk page, active talk pages for several key policies and processes, including articles for deletion, images and media for deletion, miscellany for deletion, redirects for deletion, stub types for deletion, categories for deletion, and now even user categories for deletion -- all of these filled with active discussions and, more often than not, subpages.
This doesn't yet factor in the various abuse boards, including admin intervention against vandalism, ISP abuse reporting, long-term abuse profile pages, suspected sockpuppet cases, requests for checkuser, open proxy checking, and now a seperate usernames for attention page.
Don't forget dispute resolution! We have wikiquette alerts, requests for third opinions, requests for comment, straw polls, the mediation cabal, the mediation committee, the arbitration committee, and of course countless user and article talk pages.
This is before we even consider addressing the issue of mailing lists. wikiEN-l, foundation-l, wikipedia-l, announce-l, unblock-en-l, wikitech-l, and who knows how many others. Let's not even talk about IRC, for the moment.
This is all from memory, by the way. I'm probably forgetting a few.
If memory serves, the admin noticeboard's header template linked to about ten pages, when I first came to en.wikipedia. Since then, the conflict of interest noticeboard, the biographies of living persons noticeboard, the usernames for attention noticeboard, the community sanction noticeboard, the fair use galleries noticeboard, and now today the fringe theories noticeboard have all been added to that list. Only one has been closed, that I can recall, and there's sixteen linked, currently. That's a 60% increase in "central" noticeboards in about a year.
I get the feeling I'm really beginning to see what people mean, when they say it's difficult to get things to scale, at this level.