Facebook have admitted to tracking non-users, also referred to as "shadow profiles". In a report published by Belgian academics, it is 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 responded this week saying that cookies might have been placed in some cases and that they were addressing those. They rejected outright the rest of the claims made in the report. Apart from a bug that tracked all users who visited certain Facebook pages, Facebook doesn’t practice tracking non-users, the company said in response to the report.