Check out this video from SciShow which goes some way to explaining how an email gets from your computer to another.
Emails get routed through a series of computers to reach it’s destination. It’s not a direct connection from your computer to another. That’s important to all email users because it means:
Privacy – any of those computers can make a copy of your message (unless it’s encrypted). That copy can go to a hacker, criminal, the company running the computer or a government. Just one reason why you should NEVER put a password, credit card or other personal details in a plain text email.
Spam filtering – emails go through one or more spam filters before reaching the destination. The video mentions the difficulties in figuring out if a message is spam or not. It doesn’t mention the problem of genuine messages being wrongly stopped as spam.
The video talks about email message headers, we’ve talked about a nifty tool to analyze an email header.
