When Max Schrems, an Austrian privacy activist, requested to see his personal data that Facebook stored on its servers, he was mailed a CD-ROM containing a 1,222-page document.
That file, which would stretch nearly a quarter of a mile if printed and laid end-to-end, offered a glimpse into Facebook's appetite for the private details of its 1.65 billion users.
The information included phone numbers and email addresses of Mr Schrems' friends and family; a history of all the devices he used to log in to the service; all the events he had been invited to; everyone he had "friended" (and subsequently de-friended); and an archive of his private messages.
It even included transcripts of messages he'd deleted.
But Mr Schrems, who says he only used Facebook occasionally over a three-year period, believes a sizeable chunk of information was withheld from him.