A friend asked me over the weekend: "What’s wrong with WhatsApp?"

If messages are encrypted, what’s the big deal? That’s a fair question. The answer reveals a larger problem. The problem with companies (in this case, Facebook) collecting metadata around your data.

Let's see why this is dangerous.

What’s a metadata anyway?

Data-hungry companies often defend themselves with this misleading statement: "It's OK, it's just metadata."

Well, what's a metadata? It's data that's about other data. For example: In a chat app, if the message is the primary data, then the metadata could be:

• The time of the message
• Who you're talking to.

Something like "Ben sends 1 message to Jack today at 18.33"

It's not OK at all.

Why are metadata dangerous?

Metadata collection is harmful to privacy. One single metadata may be harmless, but the more metadata you have, the more complex and precise a picture of you emerges. Let's not forget, metadata come from a variety of sources.

Let's go back to our example

"Ben sends 1 message to Mark today at 18.33"

That's pretty innocuous, right ?

But when Ben sent the message, WhatsApp (and by extension, Facebook) collected its location. If Ben sent 5 messages over 10 minutes without changing location, Facebook knows Ben isn't moving too much.

It turns out, Ben is sitting in a waiting room. Waiting to see a discernment counsellor. That's a therapist for people thinking about divorce. Ben wants to work on himself to save his marriage.

Facebook knows who Ben is married to already. They know it from an Instagram story of the wedding posted by one of Ben's contacts (even if Ben himself isn't on Instagram).

Now, from this piece of metadata (his location), Facebook can guess that Ben's marriage isn't doing well.

Before Ben even left the waiting room, his wife Sarah received an ad¹ for a divorce lawyer. 15 minutes later, Sarah sees another ad for a dating app.

You see, even a series "simple metadata" can reveal a lot about you.

This is not limited to Facebook. Anyone with metadata about you can run very complex algorithms and profit from it.

If your bank starts speaking about "sharing data with trusted partners," you should opt-out. Immediately. Now you know how they can make money from your location and card purchases.

1. Facebook sells information to advertisers everywhere on the Internet, not just on its platform. So Ben's wife can see the ad anywhere on the Internet, even if she's not on Facebook. ↩