How Does an Email Find You?

Step 1 of 5

The part after the @ is the address.

Everything before the @ is a name inside one organisation; everything after says which organisation. Sorting the internet's mail only needs the second part.

Step 2 of 5

Servers look up who handles that name.

The sending server asks the internet's directory which machine handles mail for that domain, then contacts it directly. If that machine is busy, it waits and tries again for days.

Step 3 of 5

It is not carried to your device.

The message sits on a server. Your phone or laptop connects and asks whether anything new has arrived — which is why mail appears when you open the app, not before.

Step 4 of 5

Anyone can write any name on the envelope.

Email was designed among people who trusted each other, so the sender's name is simply typed in. Everything since — spam filters, verification records — has been patching that.

Step 5 of 5

Filters guess, and sometimes wrongly.

A filter scores each message on the words, the sender's history and how many identical copies went out. High scores go to spam — and occasionally something you wanted goes with them.

Email is one of the oldest things on the internet, older than the web by more than a decade, which is why it works everywhere and trusts everyone.