What is a VPN?
A virtual private network (VPN), can help you secure your web traffic and protect your anonymity online from snoops, spies, and anyone else who wants to steal or monetize your data.
What is VPN? How does it work?
VPN creates a virtual encrypted tunnel between you and a remote server operated by a VPN service. All external internet traffic is routed through this tunnel, so your data is secure from prying eyes. Best of all, your computer appears to have the IP address of the VPN server, masking your identity.
When your data reaches the VPN server, it exits onto the public internet. If the site you're heading to uses HTTPS to secure the connection, you're still secure. But even if it was intercepted, it's difficult to trace the data back to you, since it appears to be coming from the VPN server.
In order to understand the value of a VPN, it helps to think of some specific scenarios in which a VPN might be used. Consider the public Wi-Fi network, perhaps at a coffee shop or airport. Normally, you might connect without a second thought. But do you know who might be watching the traffic on that network? Can you even be sure the Wi-Fi network is legit, or might it operated by a thief who's after your personal data? Think about the passwords, banking data, credit card numbers, and just plain private information that you transmit every time you go online.
If you connect to that same public Wi-Fi network using a VPN you can rest assured that no one on that network will be able to intercept your data—no other users snooping around for would-be victims, nor even the operators of the network itself. This last point is particularly important, and everyone should keep in mind that it's very difficult to tell whether or not a Wi-Fi network is what it appears to be. Just because it's called Starbucks_WiFi doesn't mean it's really owned by a well-known coffee purveyor.
Another example showing the value of VPNs is using these services to access blocked websites. Some governments have decided that it is in their best interest to block certain websites from access by all members of the population. With a VPN, those people can have their web traffic securely tunneled to a different country with more progressive policies, and access sites that would otherwise be blocked. And again, because VPNs encrypt your traffic, it helps protect the identity of people who connect to the open internet in this way.
What is VPN will not do
We should note that there are multiple ways your behavior can be tracked online—even with a VPN, things like cookies allow web services (Amazon, Google, Facebook, and so on) to track your internet usage even after you've left their sites (here's a handy guide to pruning cookies on your browser.)
VPNs also only anonymize your online activities so much. If you really want to browse the web anonymously, and access the dark web to boot, you'll want to use Tor. Unlike a VPN, Tor bounces your traffic through several server nodes, making it much harder to trace. It's also managed by a non-profit organization and distributed for free. Some VPN services will even connect to Tor via VPN, for additional security.
It's worth noting that most VPN services are not philanthropic organizations that operate for the public good. While many are involved in progressive causes, they are all still for-profit organizations. That means that they have their own bills to pay, and they have to respond to subpoenas and warrants. They also have to abide by the laws of the country in which they officially reside.
It's easy to want to find the perfect, magical tool that will protect you from all possible threats. But the honest truth is that if someone targets you specifically and is willing to put forward the effort, they will get to you. A VPN can be defeated by malware on your device, or by analyzing traffic patterns to correlate activity on your computer to activity on the VPN server. But using security tools like a VPN ensure that you won't be an easy target, or get scooped up in mass surveillance.