As previously reported, Facebook has been blocking some apps from accessing data - namely the newly launched Wonder from Yandex and Twitter's new Vine video app, which Facebook has reportedly kept from utilizing the Find Friends API.
Facebook issued a response to concerns about its Platform today in a post on its Developers Blog. Facebook's Justin Osofsky writes:
For the vast majority of developers building social apps and games, keep doing what you’re doing. Our goal is to provide a platform that gives people an easy way to login to your apps, create personalized and social experiences, and easily share what they’re doing in your apps with people on Facebook. This is how our platform has been used by the most popular categories of apps, such as games, music, fitness, news and general lifestyle apps.
For a much smaller number of apps that are using Facebook to either replicate our functionality or bootstrap their growth in a way that creates little value for people on Facebook, such as not providing users an easy way to share back to Facebook, we’ve had policies against this that we are further clarifying today (see I.10).
We are committed to helping you build great apps with Facebook, and will continue to invest in products that help you succeed while creating a healthy ecosystem.
So, don't do things that Facebook already does, or piggyback off Facebook's data in a way that does little to help Facebook users is pretty much the message they're sending. In a statement to TechCrunch, Yandex already explained why it felt it wasn't violating Facebook's policies, before Facebook even pulled the data, but clearly that didn't help. The companies, according to that publication, are talking about how to proceed.