I know the way the wiki calculates the page count is a mystery and potentially sketchy, but when the number shows 99,000 (which happened yesterday, 30-October-2013) it is a ton of pages!
What does this mean? Not much in the larger scheme of things, but it does mean we're very close to the even bigger number: 100,000 pages. So you may get harassing notices from the admins about a push to 100K. We'll definitely try to make it part of a contest with some kind of prize or prizes. Most likely it will be some swag from BlizzCon 2013, but who knows?
WoWWiki hit around 50K pages in late 2007, only about 3 years after it started, so growth has clearly slowed since then. So many pages to add! After BlizzCon I'm going to look into ways to make adding content easier, especially filling in those super-complicated templates that make WoWWiki look so good, but also make it harder to add stuff that looks nice. Some ideas include better boilerplates (including new ones for things like battle pets, glyphs, etc.), third party tools that work with your browser to quickly fill-in stuff (on the Mac, I use TextExpander), and if possible, some in-wiki tools (like better pre-loads or template entry UI).
So how soon can we get to 100K? I'm guessing after BlizzCon, we will get there pretty fast just to keep up with announcements.