Facebook announced some clarifications regarding their policy to ensure that developers understand the proper use of UIDs in their applications.
The official statement from Facbook developer’s blog:
“Our policy has always stated that data received from Facebook, including UIDs, cannot be shared with data brokers and ad networks. Moving forward, our policy will state that UIDs cannot leave your application or any of the infrastructure, code, and services you need to build and run your application. You can use services, such as Akamai, Amazon Web Services and analytics services as long as those services keep UIDs confidential to your application.
We realize that developers may sometimes need a way to share a unique identifier outside of their application with permitted third parties, such as content partners, advertisers or other service providers. We are adding a mechanism that developers must use to share anonymous identifiers for this purpose. We will release this functionality (available via the Graph API and FQL) early next week. We encourage developers to move to this mechanism quickly and will require it on January 1, 2011.“