If you ever wanted to know how hard we are actually working here at Mozilla, just take a look at the MozillaWiki Statistics page.
At the time of writing, it says there are 18,446,744,073,709,551,054 pages that are "probably legitimate content pages":
That's roughly 18 and a half quintillion pages. Happy reading! ;)
PS: It's obviously extremely unlikely that this is a mistake. The internet doesn't lie, after all.
Update: This was filed as a bug and fixed now, which reduced the number to a boring 260... That still sounds wrong (there have to be more than that) but it's slightly closer to reality, for sure :)