After taking heat for shutting off some apps' access to friend-finding data, Facebook says it's just protecting its assets. The social network published a blog entry today, explaining that it's changed its policies to clarify this stance. Facebook didn't respond to press inquiries yesterday about why it had shut off access to its application programming interface, or API, for a number of apps. Access to the API allows developers to add features like Facebook logins and Facebook friend searches.facebook at schoolget on facebook Facebook's director of platform partnerships and operations, Justin Osofsky, wrote in the blog that the company has received questions about the action over the last several days and has "clarified" its developer policy in response: 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...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.facebook at schoolunblock facebook Facebook is saying that if the app doesn't contribute to Facebook's platform -- like letting users share content created on the apps to Facebook -- the app can't use the social network's data. This is the stance Twitter took last year. It shut off access to its API for apps, including LinkedIn, Tumblr, and Facebook's Instagram, shortly after announcing that it was cracking down on developers who didn't help its bottom line.facebook at schoolfacebook proxy Oddly, Facebook shut down the API for video-sharing app Vine -- Twitter's latest acquisition -- as well, despite the fact that the app allows users to share their 6-second video loops to Facebook. Facebook's policy also includes language about apps duplicating any of Facebook's "core" products and services, so maybe the videos are just too close to home.