Monthly Archives: January 2013

One of the reasons I started to develop the netvizz application, was to get better insights into how Facebook envisions exchange of data and functionality with third party developers. From the beginning, I was quite amazed how much data a third-party app could actually get from the platform – not only about the users that actually install an app, but also about their friends and the groups they are members of. I hope to provide a systematic account of what I’ve learned at some point in the future. But today, I want to discuss a particular element in some more detail, the “read_stream” permission.

To introduce the matter, a couple of points concerning the Facebook APIs as such: every application written by a third-party developer requires a logged in user and this user defines the “scope” of data access the running instance of the application can get – remember that applications are generally used by many users, so the data gleaned from individual scopes can be combined. Applications have to explicitly ask for permission to access certain items and Facebook provides extensive documentation on the permission system, the profile properties, and a set of extended permissions. Users are asked to grant these permissions when they first start an app. This is the permission dialogue for netvizz:

Netvizz currently asks for the following permissions: user_status, user_groups, friends_likes, user_likes, and read_stream. When installing, you cannot refuse individual elements that are not considered “extended permissions”, only decide to not use the app at all. The user_status is actually superfluous and will be removed in the next iteration. The user_groups permission is needed to access group data and both _likes permissions are used for netvizz’ like network functionality.

Now, working on a couple of new features over the last months, I started to get more interested in posts because they have probably become the closest thing to a “carrier of publicness” on the Facebook platform. I was quite amazed how easy it was to extract large numbers of users and (some) of their data from pages – both likes and comments users make on post on or by pages are in principle up for grabs. When doing some housekeeping recently, I noticed that some of the “engagement” metrics netvizz had provided for users’ friends in earlier versions were either broken or outdated and I decided to simply count the number of likes and posts friends make to replace the older metrics. I expected to only be able to read likes – through the friends_likes permission – and public posts. This was indeed true: in the beginning, all I got were public posts. Because I could get much more data through the Graph API Explorer, a developer sandbox that asks for all permissions by default (which can be changed, a great way to explore the permission structure), I discovered the read_stream permission.

The read_stream permission is presented by Facebook in the following way: “Provides access to all the posts in the user’s News Feed and enables your application to perform searches against the user’s News Feed.” It is a so-called “extended permission”, the developer doc noting that “Extended Permissions give access to more sensitive info and the ability to publish and delete data”. And, indeed, when asking for read_stream in netvizz, I suddenly got access to many more posts made by my friends, mostly going from “none” to “a lot”. From what I could gather after some random testing was that I basically got access to all of the activities from my friends that would show up in my newsfeed, without the “top stories” filter. Because many things have the status of “post”, I could get a rather detailed (and timestamped) account of what my friends are doing on the platform. You can check out your own “posts” feed by following this link into the Graph API Explorer. Because comments and likes by users who you are not friends with on posts by somebody you are friends with also show up in your news feed, the read_stream permission allows to capture their activity as well. Facebook seems to be aware of this: because read_stream is an extended permission it gets its own permission dialogue and can actually be skipped:

This is a good thing, but the wording seems a bit sparse: “Posts in your newsfeed” actually translates to “a minute account of your friends’ activities”. Granted, buried in the privacy settings is an option that allows us to modify more generally what information we share with the apps other people use, and these are the default settings:

It’s the “Activities, interests, things I like” option that allows the read_stream permission to work its magic. The people I am friends with on the platform are generally a rather privacy conscious bunch, but I could get the posts from most of them.

This is not a privacy scandal of any sort, measures are in place, but one can still make a couple of points:

  • Apps as means for data capture are clearly not discussed enough. For serious data collection, however, going through the API is clearly the way to go and we need to pay more attention to this.
  • Again and again: defaults matter. As seen above, the data available to apps used by friends is quite extensive with default settings.
  • Again and again: language matters. The read_stream permission dialogue is certainly not explicit enough. Also: why is “app privacy” not in the privacy tab here?
  • When we log into a third party site with our Facebook login, we are basically running an app. May be worth pondering what data we are shipping over.

Exploring APIs as important actors in the privacy debate and beyond is crucial. It’s often complicated work, though, and I hope that the developer community can help with that work a bit. It would be highly useful, I think.