The one I saw said that 2% of players were paying customers, but that's been a while so it could be dated or I could be wrong. In any case, yes. It's designed to subsudise the game based on people with a lot of free cash.geldonyetich said:I seem to recall that some F2P developer released the stats of their F2P game (not FireFall), and it's something like 95% of the players don't pay anything, but the remaining 5% of the players end up paying so much that they more than make up for it. Here's a link [http://www.gamasutra.com/view/news/192899/Heres_how_much_whales_spent_so_far_this_year.php] about an example of a cell phone game microtransaction model, which is a similar situation.
It would seem F2P games work because of wealth disparity. For some people, they have so much money that the idea of dumping $250 on micro-transaction goods has no impact on them. Microtransactions are flexible in this regard; monthly subscriptions alone can't exploit that market.
Hell, look at how costly battles in EVE Online can get.