Facebook admits tracking non-users and those that opted out, but says it was by mistake

Responding to high-profile report by Belgian academics, Facebook denies damning claims about how it uses information

Facebook has written a long blog post rejecting a report that claimed it had spied on its users, accepting only one claim and saying it had been tracking people by mistake.

A report published last week by Belgian academics alleged that Facebook had been secretly installing tracking cookies on users’ computers, even when they had deleted their account and asked not to be followed. Facebook this week responded that such cookies may have been placed in “a few instances”, but that the team is addressing those “inadvertent instances”.

Facebook rejected outright the rest of the claims made in the report.

The academics had claimed that Facebook continued tracking people when they opted out of ads, but the site said it only kept information like “web impressions” — the fact that certain pages have been visited — and the authors of the report had misleadingly called that “tracking”.

It also rejected claims that “There’s no way to opt out of social ads”, that such opt outs didn’t apply across all devices, that the site is unclear about how its ads works, that Facebook gives third-party apps too much information, and more.

It laid out all of its objections in a post titled “Setting the Record Straight on a Belgian Academic Report”, and written by its vice president of policy in Europe, Richard Allan.