Each vote from commercial games count for two votes because they are better games and the people who play them love their games twice as much.  Which makes sense because people pay for them when they could be playing for free.

That or maybe this has something to do with it:

Gemstone III ad blurb:

Uh, I hope the "each vote counts double" comment was sarcasm... As far as I know, there is no such weighting for commercial muds. And don't make blanket assumptions that a commercial game simply because they charge for their service is a better game, or that the players of games who do not pay to play love their game any less...

I would think that the jump in votes is due more to the size of the playerbase than anything else...

Terloch:
Yep, the entire post, except for the last few lines where I attempted to answer the question, was sarcasm.  Thought I would have a little fun with the witchhunting mentality of the question.  I get the "was that sarcasm?" question alot,  not sure if that means it was good or bad use of it. I will try my best to use sarcasm tags in the future, a good habit that I unfortunately have fallen out of.

That's one thing I love about Armageddon... we only have around fifty online at our busiest times and are free, yet we remain in the top 20, usually the top ten. No mention of this site is made anywhere except for little buttons on the homepage and board, yet there we are.

Dedication counts for a lot, and I guess if you're paying to play your game, then you're probably more dedicated than those games that have 1000+ people online who are only passing/powergaming.