How do creators make money through their free video games?

there are a lot of free mmassive multiplayer online and multiplayer games out there, and most of them you can play for free. how do the creators make money then to maintain the site, servers, gamemasters etc. it must cost a lot of money, why make a game for free, why do they do that?How do creators make money through their free video games?
Usually through advertising. Some companies receive sponsorship. Advertising is the main route though.
"Free-to-Play" MMOs usually uses a cash shop system, in which they offer cool items in exchange of real money. Others, like Anarchy Online and some browser games, and even most websites, uses in-game advertising. There are, of course, a few that relies on donations to survive or don't care about the money. (Wikipedia, though not a game, is an example of the latter. No advertising, just donations.)



And for the reason to make "free" games is that, strangely enough, it makes more money. Lord of the Rings Online actually managed to increase their profits by 1000% (yes, a thousand) after going "Free-to-Play". Team Fortress 2 also makes a lot of money out of selling hats. Consumer behavior behaves in a very mysterious way =]How do creators make money through their free video games?
Ads, marketing ploys such as selling plushies and t shirts. Pretty much how it works, I know people who run free live streams of various games like Starcraft 2 and Battlefield 3 who don't force people to pay to watch them, but by having ads shown on their stream, earn revenue which earns em a lot of money per viewer. It's likely that Angry Birds earned a lot of money on the millions of people who played their game and had ads shown. We are talking 5 - 25 cents an ad, multiply that by say, 200 million which is not an unfair estimate of how many people played Angry Birds and you have (10 x 200,000,000) = 2 billion dollars earned. So yeah, a fair bit of money. That is if my math isn't bum xD
Advertising and cash shop sales primarily. It doesn't cost nearly as much money as you'd think to run these smaller games. They don't have hundreds of servers like World of Warcraft.How do creators make money through their free video games?
Games like that usually have ads or payed add-ons. For example, the free version of Angry Birds has ads throughout the whole game, that's how they get money