The internet is essentially computer telephoning each other. Back in the day it was literally that. When we were still on dial-up you, couldn’t use the home the phone and be on the internet at the same time. Now we have dedicated lines for internet, and instead of a phone number you have an “IP address”. When you type in a URL, that gets converted to an IP address behind the scenes by something called a DNS. Just think of a DNS as a yellow pages for the internet.

So some website you want to visit has a phone number or IP address, but your computer also has an IP address. When you connect to a website you leak two prices of information:

1. Your internet service provider (ISP) (att, charter, Verizon (etc) knows what website you’re visiting, because its connecting you to it.
2. The website you connect to knows who you are because it knows your IP address.

A VPN protects you from leaking both of those. Instead of connecting to any website directly you connect to a the VPN instead and the VPN then connects to whatever website you actually want.

So your ISP only sees they you are connecting to the VPN and the website you want to visit only sees a connection coming from the VPN. This protects your privacy from both of those parties. However, now your VPN knows both. So you must trust the VPN to not keep any records of your internet usage.

Another thing I want to point out that most people miss. The usage I described above isn’t really using a VPN as a VPN (virtual private network), but youre really using it as a Proxy. VPNs allow you to keep multiple devices on the same network even though they aren’t physically onthe same network.

If you have a home router, all of your devices connected to that router can communicate with each other without communicating through the internet. This is because they are all on the same “Local Area Network” or LAN. Nothing outside of the network can access your devices unless your router allows them too. A Virtual Private Network acts like a fake router. So if you get a VPN and connect multiple devices to it, say your laptop and your phone, then both of those devices can communicate with each other as though they were on the same WiFi. This is actually the primary purpose of VPNs, they don’t act like proxies unless you configure them to route all your traffic for you. Commercial VPN sellers however, taut that feature, enable it by default and usually leave the other feature off by default.