Posts tagged ‘google buzz’

Privacy is not Access Control (But then what is it?)

In my previous article on the Google Buzz fiasco, I pointed out that the privacy problems were exacerbated by the fact that the user interface was created by programmers. In this post I will elaborate on that theme and provide some constructive advice on privacy-conscious design, especially for social networking.

The problem I’m addressing is that as far as computer scientists and computer programmers are concerned, privacy is a question of access control, i.e., who is allowed to look at what. Unfortunately, in the real world, that is only a tiny part of what privacy is about. Here are three examples to make my point:

1. Dummy cameras. Consider a thought experiment: suppose the government installed a bunch of cameras all over a public park along with prominent signs announcing 24×7 surveillance. The catch, however, is that the cameras have not been turned on. Has anyone’s privacy been violated?

From the computer science perspective, the answer is no, because no one is actually being observed, nothing is being recorded and no data is being generated. But common sense tells us that something is wrong with that answer. The cameras cause people considerable discomfort. The surveillance, real or imaginary, changes their behavior.

This hypothetical scenario is adapted from Ryan Calo’s paper, which analyzes in detail the “sensation of being observed.”

2. Aggregation changes the equation. Remember the uproar when Facebook released News Feed? No new information was revealed to your friends that wasn’t accessible to them before; it was just that the News Feed made it dramatically easier to observe all your activities on the site.

Of course, it goes both ways: the technology in turn changed people’s expectations; it is now hard to imagine not having a feed-like system, whether on Facebook or another social network. Nevertheless, I often see people putting something into their profile, deciding a few moments later that they didn’t want to share it after all, and realizing that it was too late because the information has already been broadcast to their friends.

3. Everyone-but-X access control, which I described in an earlier article, shows in a direct way how access control fails to capture privacy requirements. From the traditional CS security perspective, the ability for a user to make something visible to “everyone but X” is meaningless: X can always create a fake account to get around it.

But a use-case should hopefully immediately convince you that everyone-but-X is a good idea: your sibling is on your friends list and you want to post about your sex life. It’s not that you want to prevent X from having access to your post, but rather that both of you prefer that X didn’t have access to it.

Access control is not the goal of privacy design. It is at best one of many tools. Rather, human behavior is key. The dummy cameras were bad because they affected the behavior of people in a detrimental way. News feed was bad because it introduced major new privacy consequences for the behaviors that people were accustomed to on the site. (However, I would argue that the dramatic increase in usefulness trumped the privacy drawbacks.) Everyone-but-X privacy is good because it allows people to carry over to the online setting behaviors that they are used to in the real world.

It is impossible to fully analyze the privacy consequences of a design decision without studying its impact on actual user behavior. There is no theoretical framework to ensure that a design decision is safe — user testing is essential. Going back to Google Buzz, a beta period or a more gradually phased roll-out would have undoubtedly been better.

To stay on top of future posts, subscribe to the RSS feed or follow me on Twitter.

February 13, 2010 at 3:03 am 10 comments

Google Buzz, Social Norms and Privacy

Another day, another privacy backlash — this time with Google Buzz. What’s new? Lots, as it turns out.

There are many minor ways in which Google Buzz fails, both with regard to privacy and otherwise. For example, I’ve been posting my Buzz updates publicly because the user interface for posting it to a restricted group is horribly clunky. (Post only to my followers? What’s the point of that, when anyone can start following me?! Make it easy to post to a group that I have control over!)

But the major privacy SNAFU, as you’ve probably heard, is auto-follow. Google automatically makes public a list of the top 25 or so people you’ve corresponded with in Gmail or Google talk. Worse, the button to turn this “feature” off resides in your Google-wide profile, making it unnecessarily hard to find because it isn’t within the Buzz interface itself.

This is a classic example of what happens when the user interface is created by programmers instead of designers, a recurring problem for Google. Programmers partition features in a way that fits the computer’s natural data model, rather than the user’s natural mental model.

But getting back to privacy, it is a certainty in a statistical sense that Google outed a few affairs and other secret relationships. For even if you were yourself savvy enough to turn off the public display of your top correspondents, there’s a good chance the other party wasn’t, and might not have turned it off on their end.

When I enabled Buzz and realized what had happened, something changed for me in my head. I’d always regarded email and chat as a private medium. But that’s not true any more; Google forced me to discard my earlier expectations. Even if Google apologizes and retracts auto-follow (not that I think that’s likely), the way I view email has permanently changed, because I can’t be sure that it won’t happen again. I lost some of the privacy expectation that I had of not only Google’s services, but of email and chat in general, albeit to a lesser extent.

What I’ve tried to do in the preceding paragraphs is show in a step-by-step manner how Google’s move changed social norms. The larger players like Google and Microsoft have been very conservative when it comes to privacy, unlike upstarts like Facebook. So why did Google enable auto-follow? By all accounts, their hand was forced: they needed a social network to compete with Facebook and Twitter. Given the head-start that their competitors have, the only real way to compete was to drag their users into participating.

Google ended up changing society’s norms in a detrimental way in order to meet their business objectives. This has become a recurring theme (c.f. the section on Facebook in that article). I don’t think there is any possibility of putting the genie back in the bottle; this trend will only continue. This time it was about who I email; soon my expectations about the contents of emails themselves will probably change.

I believe that in the long run, the only “stable equilibrium” of privacy norms, as it were, would be for everyone to simply assume that everything they type into a computer will be publicly visible either instantly or at some point in the future, outside their control. That is not necessarily as terrible as it may seem. Nonetheless, society will take a long time to get there. Until then, the best we can do is push back against intrusions as much as possible, delaying the inevitable, giving ourselves enough time to adapt.

Do your part to fight back against auto-follow. Let Google know how you feel. Blog about it or leave a comment.


  1. A New York Times blogger picked up the controversy.
  2. Joe Bonneau has an analysis of users’ confused reactions.
  3. Google has announced that it is rolling out some user-interface changes in response to the feedback. That is better than before, but the default is still public auto-follow.
  4. The horror stories due to auto-follow have begun.
  5. I have a new article with advice on privacy-conscious design.
  6. Google decided to nix auto-follow after all! Awesome.

Thanks to Joe Bonneau for reviewing a draft of this article.

To stay on top of future posts, subscribe to the RSS feed or follow me on Twitter.

February 11, 2010 at 8:47 pm 20 comments


I’m an associate professor of computer science at Princeton. I research (and teach) information privacy and security, and moonlight in technology policy.

This is a blog about my research on breaking data anonymization, and more broadly about information privacy, law and policy.

For an explanation of the blog title and more info, see the About page.

Me, elsewhere

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 260 other followers