(CNN) -- For the first time, the number of active daily visitors checking Facebook on mobile devices is higher than the number of people checking the social network on the Web.
Overall, the company says there are 1.06 billion active Facebook users in the world. Of those, 618 million of them are visiting daily and 157 million are doing it from mobile devices.
The company's focus on putting mobile first, with new apps and features, is paying off. Facebook is the largest social network in the world, and it was the most-used mobile app across iOS and Android devices in the United States in 2012, according to recent comScore numbers.
"In 2012, we connected over a billion people and became a mobile company," said Facebook CEO Mark Zuckerberg in a statement announcing the fourth-quarter results.
This is great news for the company, which is figuring out the best way to make money off all those smartphone and tablet users. Its biggest earner is advertising, which makes up 84% of the company's revenue. The big story this quarter is mobile ads, which the company said accounted for 23% of its ad revenue, a huge leap from the third quarter of last year when it was just 14%. Big companies like Wal-Mart are tapping into Facebook's audience. The retailer served up 50 million mobile ads in the fourth quarter.
Facebook also makes some money off social games like Zynga's "FarmVille," which share revenue with the social network. But the company is hoping to move beyond Zynga's games to become the default platform for mobile games from all developers.
The company is constantly testing new ways to squeeze cash out of users and partners, with a steady stream of features and ads. Recent smaller projects that are still finding their legs include Facebook Gifts, which lets you buy real and virtual goods for friends, and charging a small fee to send messages to strangers.
While ads and visits are taking off on mobile devices, the company's latest big feature is still Web-only. Graph Search, a new advanced search feature that lets you scour your extended network for people based on their likes or profiles, is still in its beta stages and cannot be accessed through mobile apps.
Currently the search feature doesn't make money, but Zuckerberg said it could become a meaningful business "down the line."