Feeds

Many sites cookie-track users regardless of opt-outs

Google's clean, though, say researchers

The Essential Guide to IT Transformation

More than 10 per cent of companies that promise not to track internet users' online activity for behavioural advertising purposes still do so, according to new research.

Publishers and advertising networks use cookies to track user behaviour on websites in order to target adverts to individuals based on that behaviour. A cookie is a small text file that websites store on users' computers to remember their activity on a site.

Researchers at Stanford Law School investigated whether companies belonging to a voluntary scheme run by the Network Advertising Initiative (NAI) actually complied with the rules they had signed up to.

The NAI encourages online businesses to voluntarily adopt a set of rules governing online behavioural advertising. Those rules force member companies to tell users that cookies they store about them could be used to serve behavioural ads. The rules also state that member companies must stop using the cookies to serve ads if asked to by users.

The researchers claimed that at least eight NAI members out of the 64 they investigated continued placing behavioural ad cookies on researchers' machines after being asked not to.

"At least eight NAI members promise to stop tracking after opting out, but nonetheless leave tracking cookies in place," Jonathan Mayer, one of the Stanford researchers, said in a blog.

Mayer said that the researchers had performed three tests of the NAI members' cookie promises. In some of the cases the companies did delete the cookies but the researchers found that they were restored after they revisited content on the website, Mayer said in his blog. In other cases some of companies deleted some cookies and not others, he said.

One of the eight firms, Vibrant Media, did not delete any of the tracking cookies when asked, the researchers claimed.

More than half of NAI members tested left tracking cookies in place after researchers had told websites they were opting out. Researchers said that NAI members only have to allow users to opt out of behavioural ad targeting and not tracking.

"Of the 64 companies we studied, 33 left tracking cookies in place after opting out," the researchers said.

At least 10 NAI members, including Google, delete tracking cookies as well as behavioural ad targeting, the researchers said.

See the Stanford researchers' blog here.

Copyright © 2011, OUT-LAW.com

OUT-LAW.COM is part of international law firm Pinsent Masons.

Build a business case: developing custom apps

More from The Register

next story
14 antivirus apps found to have security problems
Vendors just don't care, says researcher, after finding basic boo-boos in security software
'Things' on the Internet-of-things have 25 vulnerabilities apiece
Leaking sprinklers, overheated thermostats and picked locks all online
iWallet: No BONKING PLEASE, we're Apple
BLE-ding iPhones, not NFC bonkers, will drive trend - marketeers
Only '3% of web servers in top corps' fully fixed after Heartbleed snafu
Just slapping a patched OpenSSL on a machine ain't going to cut it, we're told
How long is too long to wait for a security fix?
Synology finally patches OpenSSL bugs in Trevor's NAS
Israel's Iron Dome missile tech stolen by Chinese hackers
Corporate raiders Comment Crew fingered for attacks
Tor attack nodes RIPPED MASKS off users for 6 MONTHS
Traffic confirmation attack bared users' privates - but to whom?
Roll out the welcome mat to hackers and crackers
Security chap pens guide to bug bounty programs that won't fail like Yahoo!'s
Researcher sat on critical IE bugs for THREE YEARS
VUPEN waited for Pwn2Own cash while IE's sandbox leaked
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.
Maximize storage efficiency across the enterprise
The HP StoreOnce backup solution offers highly flexible, centrally managed, and highly efficient data protection for any enterprise.