A virtual private network (VPN) may confuse some people. At it's core, a VPN is a private network that is made available to authorized users from the internet. Examples of a private network would be the network at your work, at college, or government locations.
Those networks have internet access, but the internet does not have access to them, hence the term private network. The private network becomes virtual when you are able to access it from the internet. The internet still does not have access to the private network, but your computer does. As far as the private network is concerned, your computer connection is at work or school.
When you connect to a VPN, you are connecting to a set of servers over the internet. This process is known as tunneling. Anything you do on the internet will go through these servers. All of this data is encrypted, which provides great privacy for you.
As far as your internet service provider knows, you're connecting to some IP address. They cannot see what the data is or anything.
The most important, and obvious, reason is security. As we stated above, all of your internet data is encrypted once you have created that tunnel. Hackers, for example, would not be able to intercept your internet browsing activity. Hackers will often attempt to do this when you use public WiFi in places like coffee shops and airports. If you make a purchase with your credit card on public WiFi, hackers could get a hold of your credit card number. This is why you should use a VPN.
A secondary benefit, which ties into security, is privacy. Because all traffic is encrypted, all data secure and private. What you search for, watch, read, or listen to is your own business. You ISP and hackers will not know what you are doing online.
VPNs will not, however, protect you from tracking by various website trackers, such as cookies.
VPN provides encryption to network traffic. It ensures the communication cannot be easily eavesdropped/tampered with by adversaries. It does not impact application features like cookies. So yes cookies can still be set on your browser if you are tunneled through VPN.
Ximning Ou from the University of Southern Florida
In order to prevent these tracking efforts, you can surf the web with your browser's incognito/private mode. Another option would be to install an extension that prevents this, like ghostery.
Another reason for using a VPN? Virtual locations. Many providers will have servers in multiple locations. This was an option many Netflix users chose to access content that was not available in their region. Just because content has a block in your country, does not mean it is in another country. All you need to do is tunnel into a VPN server in a country that does not have the block, and you will have access.
The same works in reverse too. For example, you're traveling out of the country but your bank blocks access to users outside of your homeland. You can use your VPN to tunnel to a server located back home to gain access.
On a side note, just because using VPN allows your to potentially bypass restrictions, do not forget you are still operating under your countries laws. VPNs will make you anonymous online, not invisible. If you start doing anything illegal or suspicious. Given enough time and resources, government agencies could, in theory, still find you.
Today, there are tons of VPN providers to choose from. Some providers are great, some are not. Below are some things to consider when choosing a VPN provider:
One of the biggest drawbacks is internet speed. Depending on the provider, you will see reduced internet speeds. Sometimes, the reduction is small, other times its large. It all depends on the number of users connected to the same server as you, the location of the server, and the providers setup. Longer distances between you and your VPN server means longer distances for data to travel in order to reach to the internet.
A secondary, and minor, issue is that when you use a VPN as a virtual location, you can see some issues while shopping. Say you live in the US, but have a connection through a tunnel in the UK. While shopping online, your pricing may show in pounds instead of US dollars. The simple solution is to use a server in your country while shopping online.
Using a VPN is becoming more of a necessity each day. The krack attack has proven that access to home WiFi traffic can occur. Connecting to a VPN service protects you from this vulnerability. Ensuring you have a good VPN provider will help ensure you are better protected.