Curious as how exactly Facebook makes their money?

Advertising

See all the ads on the side when you're on FB? People pay for that space...I have an advertising campaign going on right now using FB. It's not huge money but when you add up how many ads per day they actually run, it becomes huge money overall.

Ads. There are millions of users on FB, it's top ad space. Think of it as a TV show. The ones that do well have companies paying millions for ad space via commercials. The more popular the show, the more they sell ad space for. Same with FB. They don't put up those ads for free, the advertisers pay a premium to be on that site because of its popularity.