It was an API for making apps with Facebook integration, and after they closed it down, Facebook became even more of a walled garden. Perhaps no criticism of Facebook has ever been more trumped up, and it shut down a lot of people making useful, fun, interesting Facebook apps who were afterwards locked out of the platform. Facebook was probably all too happy to remove the functionality and use this as the excuse to do it.

Anyone that remembers the Graffiti Wall knows the real thing that was lost here. It had it's issues (Farmville was the worst / most annoying version of Harvest Moon ever made) but it was worth saving.

It was also worth building the infrastructure required to make it function, because it ultimately damaged Facebook in ways I don't think they really still understand. Their abortive attempt to build a metaverse or a Twitter that feels more like a prison, vs successful, beautiful, creative, wild interpretations of a metaverse that lead to things like Minecraft and Bluesky. They simply won't succeed a these endeavors without meaningful third party access. Improving upon that problem might be a more productive use of their time than kissing political butts if they want to actually succeed in this space.