Monday, March 7, 2011

Comprehensive Guide to Twitter Privacy: Who hears what you say?

Comprehensive Guide to Twitter Privacy

I've become fascinated with how Twitter has such simple settings, and yet Twitter privacy is in many ways quite complex, so I'm starting to put all of this information together. This is part 1 of... many.

[Part 1: Who hears what you say?] <-- you are here! [Part 2: Where are you?]

Note that many of the things I'm saying here are true of other social networks or any place you might share information online, but I decided this would be most readable with examples from one site, so I've decided to use Twitter, which I like and use regularly.

Part 1: Who hears what you say?

On the surface, Twitter has perhaps the simplest privacy policy of any social network:

Either everyone can read your tweets (everything you say on twitter is public) or you can make your feed private (and then maintain a list of people who are allowed to see it).

You also, regardless of which option you choose, have the option of blocking individuals from following you. Blocking someone isn't hugely effective if they can then log out and read your public feed anyhow, but it can cut down on spam.


Blocking everyone you don't know is not necessarily the end of the story. Just like gossip, anyone who can read what you've said can also share it. It's fairly common in twitter parlance to "retweet" a message: that is, repeat the message verbatim or sometimes with small edits for length or the addition of commentary.

When you have a public account, retweeting is pretty much harmless behaviour. Anyone could see that funny thing you said if they looked, so if one of your followers retweets it, you're really just winding up with a few more strangers seeing it than you might otherwise. But they could have looked at that tweet at any time if they so chose. Often it's a really positive thing: more people get to hear about a cause you believe in or something cool you've done.

However, the story can be quite different if you have a private account. Perhaps you have chosen to keep your account private because you and your boss don't share political views. That "funny" thing you said could become seriously awkward if she winds up seeing it retweeted. Probably you chose to make your account private for a reason, and retweets can violate your expectation of privacy.

Violating privacy with retweets?

There's actual a whole paper on this subject that appeared in Web 2.0 Security and Privacy 2010. It has the cheesy-cute title RT @IWantPrivacy: Widespread Violation of Privacy Settings in the Twitter Social Network. They found that while some clients did block users from retweeting private feeds, many didn't and of course users could always just type RT and repeat the whole message anyhow. The researchers collected 4.42 million tweets that were exposing private information in this manner, and they expect that the numbers will continue to climb.

It's hard to tell, however, whether those millions of exposed tweets were really problematic for the people who wound up exposed, however. Perhaps millions of people asked before retweeting (something you should always do before sharing private information, but I know even I forget to do this sometimes when telling a good story I heard, so I suspect retweeting is no different). Perhaps most of the tweets were cute pictures of cats that no one really minded sharing. But either way, you should be aware of what you retweet and aware of what you say that could be retweeted.

RETWEET @josef (Experiment)

Retweeting lies

It's also worth noting that even though researchers assumed that most of those tweets were actual privacy exposures, it's equally possible that many of them were made up. If someone can type RT and your name and cut and paste in the message, there's no reason that it has to be your message that they post in. Often edits are minor, but there's nothing stopping one from going RT @twitter we hate kittens or something significantly more damaging to someone's reputation. Without a public feed, it's hard to refute since no one can check what you said, and even with a public feed people may expect that you deleted the offending message. A recent defamation lawsuit in the US may serve as a reminder that what you say and what you seem to say on twitter could have real implications.

So that little checkbox? It's clearly not the end of the story.

Stay tuned for Part 2 next week!

[Part 1: Who hears what you say?] <-- you are here! [Part 2: Where are you?]

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