Even a casual Facebook user can see that the site has changed dramatically over the past year. On Thursday, Facebook’s developers team took some time to reflect on some of the highlights that made the social network what it is today.

One of the major stories for developers was the adoption of open graph technology, which opened to a much wider audience in 2012. Several applications, such as Songza and Nike+ Running, made use of open graph to expand their influence to new users. Facebook also included location and friend tagging to enhance open graph actions. Apps in the categories of fashion, fitness, social good, and music were especially popular in 2012.

Improving the app experience was paramount in 2012, as Facebook worked with the developer community to bring new, improved apps to the site’s user base. Facebook counted several successes with regard to improving apps and the discovery of these apps, such as launching its app center, and other milestones, as outlined in a blog post:

• Preferred Marketing Developer program and Preferred Marketing Developer Center brought marketers more ways to integrate their apps and campaigns with Facebook platform.
• App quality insights gave you more ways to monitor the health of your app activity.
• Subscriptions and local currency pricing created more options for building a business on Facebook.
• The World Hack brought the global developer community together in cities around the world to build social apps.
• Open graph shifted to explicitly shared actions to better reflect how people interact with apps and match their expectations.
• The notifications API brought a requested one-on-one communication channel to developers with high-quality apps.
• Developer alerts gave you more ways to receive updates and monitor the health of your apps.
• Auto-generated documentation makes our documentation more accurate, complete, and up-to-date over time.

Facebook also worked extensively on enhancing the mobile experience, not just for the ever-popular Android and iOS native apps, but formats such as BlackBerry, as well. The site reported that more than 200,000 iOS and Android apps have Facebook integration, including more than 45 percent of the top 400 grossing iOS apps. Facebook also launched new software development kits for iOS and for Android, as well as introducing Facebook for iOS 6, so users of the new iPhone 5 and iPad could enjoy the richest social network experience on their mobile devices.

The third major market of improvement came with games, as several game developers (such as FreshPlanet, with SongPop) found success through Facebook’s open graph technology. Facebook Platform Head Doug Purdy explained how 2012 was a game-changer for several developers:

This was a big year for social games, as we saw greater diversity than ever before in genres, regions, and platforms. Games on Facebook.com reached more than 250 million monthly active users, and the user base also grew across top social mobile apps on iOS and Android. As the longest-standing and largest app category on Facebook, we continued to build game-specific infrastructure to support a growing and diverse games ecosystem on both Facebook.com and mobile.

Purdy pointed out that several games came from outside of the U.S., offering SongPop, Candy Crush Saga, Dragon City, and Clash of Clans as examples of internationally based hits.

Readers: What were some of your favorite Facebook apps you discovered this year?