Earlier quoted context omitted.
How did you arrive at 20 million? This sounds like one of those "technically true" facts that are cooked up for investors. http://wikis.wikia.com/wiki/List_of_Wikia_wikis puts the combined total of the top 1,000 wikis (in all languages) at 12.4m.
20 million pages, not wikis -- sorry if I mistyped?
There aren't 20 million pages. Read my comment again.