A minor security bug on Facebook erupted into a major scandal this week.

It turns out the social media site keeps files on users — and their friends who don't even use Facebook.

CBC technology columnist Jesse Hirsh explains how Facebook is gathering information and what the site might be doing with it.

The bug "allowed security researchers to look into this secret, or parallel, social network that Facebook maintains not only of Facebook users, but of non-Facebook users," he says.

Listen to Hirsh explain how you can best protect yourself.