I hear the cries of "you're crazy, yak," but hear me out on this.
It's the perfect way to get more active users - pay those that edit the most - employ them as workers for their site. You might say that this would never work, but why wouldn't it? Wikia ought to start doing the decent thing and start rewarding the people who are making the company money - i.e., us.
Instead of funding crappy copycat projects like WikiAnswers and Wikia Search -- the latter of which collapsed recently -- why not focus on the very thing that keeps the visitors coming - the editors?
And if they're so in love with advertisements, why not go all out on a 50-50 page advert to content ratio and financially reward the users; actually give something back to the very people who give up their own time, bandwidth and money to further the project.
Of course, it's never going to happen. But it would be a fun concept - paid wiki editing. I'm well aware that all the most successful wikis through time have functioned well enough with unpaid volunteers (Wikipedia et al), but is that because the founders were more interested in making money for themselves rather than rewarding their users?
Something to think about anyway.