One of the fundamental principles in Facebook services is to be open. Open makes rooms for its users and partners to take part in and eventually it, I thought, made Facebook distinguished from the similar services such as MySpace.
In a traditional approach, it is definitely silly to open platform and provide APIs. It is because it weakens the service provider in terms of the control over the service. Also, the number of visitors would decrease since users could enjoy the service via 3rd-party applications. However, Facebook opened its platform and proved that open makes improvements and success.
Interestingly, Facebook has taken advantage of openness in localizing its service. Facebook currently provides its service in almost 100 countries in their language. We can guess how much work has done for it and is needed further as the service evolves. Brilliantly Facebook opened translation works to be done and got help from its users with a very smart system: http://www.facebook.com/translations/. The quality of the translation seemed pretty good. I had once assumed the translation had been done by professionals.
Surely, there are mistakes. A few minutes ago I found that ‘performance’ is translated to ‘공연’ rather than ‘성능’ at http://developers.facebook.com/docs/guides/performance. But isn’t it cute?