Stanford Privacy Study 'Tracking The Trackers' Finds Top U.S. Sites Share Personal Data

By Julia Angwin, Wall Street Journal

A study released Tuesday shows that 45% of the top 185 U.S. websites transmit identifying details about their visitors to at least four outside websites.

The data transmitted was primarily a “username” – which is the name a person uses to log into a website – or a user ID assigned by the website to a user. It was usually transmitted through referrers – which is information about the web page transmitted automatically.

In some cases, the data went much further: the study found for instance that the online dating website OKCupid sent the gender, age, zip code, relationship status and ‘drug use frequency’ to two companies that sell personal data in auctions, BlueKai and Lotame.

Lotame confirmed that is has a data licensing relationship with OKCupid, but said it does not use data in the “drug use category.”

BlueKai told Digits that it does not buy or sell data attributes like “drug use frequency” from OKCupid. “We do capture standard demographic attributes like zip, age and gender from several publishers,” a spokesperson said.

It’s not clear how many companies that received the data used the identifying information. But researcher Jonathan Mayer, a PhD student at Stanford University’s computer security lab, said that the study proved that online tracking is not anonymous.

Read the full story at the Wall Street Journal.

More from WSJ Blogs:

• Making Privacy Notices Easier for Websites


• A New Source for Searching Google+


• Twitter Will Get “Tweet” Trademark, Settles Lawsuit

Comments

[librlsun]

07:24 PM on 10/12/2011

Why would anybody want to publicize their "drug use"?

[Scott Lambert]

02:54 PM on 10/13/2011

Because it's not illegal to say you smoke weed, and regardless of what you think, the majorities smoke weed (maybe not older generations though). Why would you want to publicize that fact if you were in a survey either? You wouldn't want to admit because of fear of unjust retaliation (just like I would lose my engineering job, but strangely it was my aerospace professor who got me turned on to it) so all the statistics are skewed anyways. Guess what.. In Alaska it's legal to smoke and grow pot for recreation. There's countless other states who have medicinal marijuana programs, and if you never speak up, then nothing will ever change. Keep hiding in the shadows and your views/beliefs will never go further that that, being your own beliefs and views. If we legalized and taxed weed, this country wouldn't be where it is today, and there wouldn't be as much violence. Dispensaries brought with them lower crime rates.

[addisonsteele]

12:47 PM on 10/12/2011

Why is anyone shocked? Companies like Google and Facebook base their business model on selling information about their users to other companies. Our private information is the product they sell. Indeed, we could probably eliminate the federal deficit if the NSA, which listens to every telephone call and examines every e-mail, went into competition with them because the NSA has access to private information that they cannot get (yet).

[bessielil]

02:49 PM on 10/12/2011

Perhaps HP should insist that the word SHOCKING be left out of all their headlines. Rarely am I shocked by what I read.

[BCSLAVE]

12:42 PM on 10/12/2011

Its nice to see the work and tools of the Gestapo are in the trusty hands of Capitalist. Where's Rupert in all this?

[beasteben]

12:10 PM on 10/12/2011

Small print should be illegal. Who the heck reads all of that?

[JustinP213]

11:52 AM on 10/12/2011

Each website should be legally mandated to seek our permission before selling our personal information. Obviously, I know that our Congress would never vote in favor of this, but that's a different story.

[Telemachus]

01:13 PM on 10/12/2011

That's because, despite their protestations, Congresscritters generally don't give a rip about individual liberty, economic opportunity, or the property rights of American citizens.

[mass maritimer]

10:57 AM on 10/12/2011

This is why I am Tek Jansen everywhere I go......A 30 year old male living in Vermont.

yep, I lie everytime I register for something....every time

My parents never gave out our accurate phone number so I thank them

[progressivestance84]

01:24 AM on 10/13/2011

Adventures in space!

[LeaderofMen]

09:45 AM on 10/12/2011

Look at your spam folder and weep. 90+% of the sites you purchase anything from, immediately sell your email address.

[Sandee McHale Delano]

08:34 AM on 10/12/2011

George Orwell 1984....he was correct, just got the date wrong.

[mass maritimer]

10:55 AM on 10/12/2011

He got the Animal Farm right too, sadly

[Whistlejackett]

08:31 AM on 10/12/2011

Guess I will just have to keep breaking copyright laws.

[MaybeMilo]

05:50 AM on 10/12/2011

"Shocking"?

Not by a long shot.

[stape45]

12:13 AM on 10/12/2011

Corporate America doesn't see us as people - we're just a bunch of dollars to them.

[ArchStanton400]

12:26 AM on 10/12/2011

True but in the end it is ALWAYS up to you to accept the sale. As long as you can say a resounding NO in the face to these salesmen and walk away knowing they are schmucks trying to sell you a bill-of-goods you'll always come out ahead. Treat them like you are Don Rickles on stage. That's the key.

[Deleuzian Nomad]

12:32 AM on 10/12/2011

nice Don Rickles reference there....

[stape45]

01:25 AM on 10/12/2011

Sometimes the only choice we have is to take the bad deal or take a different bad deal. Some neccesities must be purchased from one source or another, whether there is a fair deal offered or not. If it's something that you or a loved one must have, not making the purchase at all, just isn't an option.

[falconsso]

11:18 PM on 10/11/2011

ACLU, what say you ?

[LuLou Murder]

10:38 PM on 10/11/2011

Never. They're too busy selling your data.

[HeevenSteven]

10:04 PM on 10/11/2011

When are we going to see the tea-bagger congress make a real issue about liberty here?

[thereisonlyoneparty]

10:41 PM on 10/11/2011

What is the issue?

The companies have privacy policies and the user agrees to the ToS when they register for the site.

[radiojunkie]

08:12 AM on 10/12/2011

The issue is they shouldn't be collecting data they say they don't use. They're just data mining and waiting for the opportunity to sell and the legal loophole to escape through.