About InPrivate and Incognito: What is private browsing? What does it do? Which browser is the best?

When you want to hide something that you do online, you use a private browsing mode like Incognito, Private Browsing, or InPrivate. However, do you know how private you are when you use this way of browsing the web? Can others still see what you are doing online? Also, do you know which browser is best at protecting your privacy? We have tested Google Chrome, Mozilla Firefox, Microsoft Edge, Internet Explorer, and Opera, and we have the answers to all these questions. If you want to know all there is to know about InPrivate, Incognito and other private browsing modes, read this article:

What is private browsing? What does it do?

Private browsing is a slightly more private way of browsing the web, compared to standard web browsing. In all the major web browsers, private browsing does the following:

  • Deletes stored cookies from your browsing sessions when closing private browsing. This means that if you have logged into Facebook, Gmail, YouTube or some other website, when you close all the private browsing tabs and windows, these cookies are deleted, and you are automatically signed out. If someone else tries to visit the same websites in a new browsing window,they are not automatically logged in with your account(s). Cookies from non-private browsing sessions remain as they are.
  • Deletes the data you type in forms, like sign-up pages, login pages or contact pages. When browsing the web, you may need to enter data into all kinds of forms, manually. When you close all the private browsing tabs and windows, this data is deleted and cannot be reused by anyone.
  • Deletes temporary files and the cache from your browsing session. When you visit a website, files get downloaded to your computer or device, like images, styling files and so on. All these files are stored on your computer for the duration of your private browsing session, to make browsing faster. However, when you close all the private browsing tabs and windows, these files are deleted, so that they cannot be accessed and used by anyone else who knows where to look for them on the disk.
  • Deletes the browsing history from your browsing session. When you browse the web, the web browser stores a log of everything you have visited so that you can access this information later or autocomplete addresses when you type them in the address bar. When you browse privately, the browsing history from your session gets automatically deleted when you close all the private browsing tabs and windows. This way, other people with access to the same computer or device, cannot know what you have visited on the web, just by looking at your web browser.
  • Does not store the search history from your browsing session. In modern browsers, you can search the web straight from their address bar. You type search keywords, press Enter and they are sent automatically to the default search engine to return results. In regular browsing sessions, this data is stored for later reuse, so that you browse the web faster. In private browsing, this data is not stored at all, so that others can not reuse it when accessing the same computer or device.
What Incognito does in Google Chrome

All these things are great features that enhance your privacy and confidentiality. They are useful to protect yourself from other people who have access to the same computer so that they do not know what you are doing online. However, private browsing does not mean that no one can track you.

What private browsing does not do

Private browsing is not a silver bullet, and some entities can still track you, depending on the web browser that you are using and how it is set up:

  • The files you download and the bookmarks you save remain where you saved them. You need to delete them manually if you do not want others to see them or use them.
  • You are not protected from keyloggers and spyware. Even though the browser deletes the data that you type, keyloggers and spyware act as independent programs that intercept all keystrokes. To protect yourself from these threats, you need a good antivirus.
  • Your internet service provider knows everything that you have done online unless you use VPN alongside private browsing, to encrypt your traffic. Fortunately, some browsers offer this kind of protection in their private browsing mode. Read on to learn more.
  • If you are in an organization like a corporation, or a school, your web browser communicates with a proxy server and a Domain Name Server that is managed by that organization. This means that IT administrator(s) log your activity online and they know what websites you have browsed. To protect yourself, you need a VPN to go along with private browsing. Luckily, there are browsers which offer built-in VPN protection.
  • The websites that you visit know that you visited them. However, if you also log into those sites, they know precisely that it was you and what you have done while visiting them. If you do not log in, they know that they have a visitor. Some websites might even identify you, through more advanced tracking, which leads us to the next point.
  • Ad networks know what you visited and what you searched for. Ad networks use advanced tracking techniques that track your browsing data across multiple sites, using your IP address, browser identifier, and cookies. Some browsers offer tracking protection or at least ad blocking features in private browsing. If you enable them, it is harder for ad networks to track you. Enable a VPN connection too, and your private browsing becomes more difficult to track.

The web browsers we used for comparison and the add-ons we installed

For our comparison of private browsing modes, we used the following browsers for Windows: Google Chrome version 72 (64-bit), Mozilla Firefox version 65 (64-bit), Microsoft Edge version 44 (64-bit), Internet Explorer version 11 (32-bit), and Opera 58.

The web browsers we used for testing private browsing

We also installed the Pocket, LastPass, Amazon Assistant, and Avast Online Security extensions, to see whether they are active in private browsing and whether they track user behavior. Internet Explorer did not get Pocket and Avast Online Security because those extensions do not work in this browser.

What is the best browser for private browsing?

We tested each browser individually, and double checked that it does what promises. We also verified the following:

  • Does the browser allow you to recover a closed tab when private browsing? This is a negative feature because you may forget one private tab open and someone else can come to the same PC and restore all your closed tabs, to see what you have visited.
  • Does the browser disable extensions? If a browser does not disable them browsing privately, you can be tracked by the installed add-ons installed in your browser. This is another critical negative, especially when using browsers that have nasty toolbars and dodgy add-ons installed, like those from public places.
  • Does the browser block advertising and other types of tracking? Advertising networks have the habit of tracking users across multiple websites, to know what they want and serve ads that are more likely to get clicked.
  • Does the browser offer built-in VPN? This feature is useful when you do not want other organizations to know what you are doing online. When using VPN, your browsing is encrypted, and your internet service provider does not know what you are visiting, and neither does the organization on whose network you are on. Even advertisements are misled into thinking that you are someone else.

Below you can see a comparison of all the features that are offered in the default versions of each browser. Some Yes boxes colored in green while others are colored in red. We used red and green to signal whether a feature or the lack of it, is a positive or negative. Green represents a positive feature, and red represents a negative.

The privacy features offered by Chrome, Firefox, Edge, Opera, and Internet Explorer

As you can see in this table, the best browser for private browsing is Opera! Let's discuss each browser, one by one and see what they offer and what they do not.

Google Chrome covers all privacy basics, and that's it!

When it comes to private browsing, the Incognito mode from Google Chrome offers only the basics. It can protect you from other people using the same computer knowing what you are doing online, and that is it. It does not protect you against anything else.

Google Chrome Incognito browsing mode

Mozilla Firefox is a mixed bag when it comes to private browsing

We discovered a surprising number of issues with Firefox's private browsing feature. First of all, it allows users to restore closed tabs, even when browsing privately. If you forget one private browsing tab open, someone else can restore your closed tabs and learn what you were doing online.

Undo Close Tab in Firefox Private Browsing

Another issue and this is more serious, is that it allows all extensions to run in private browsing. If you have a dodgy extension installed, it can track you with ease.

Extensions are loaded in Firefox Private Browsing

On the other hand, Firefox is the only browser from our testing that blocked trackers by default, which is a feature that should be adopted by all web browsers.

Firefox blocks trackers by default, in Private Browsing

If Mozilla disabled extensions when browsing privately, as well as the recovery of closed tabs, it would make Firefox the best browser for private browsing.

Microsoft Edge is just as private as Google Chrome

Microsoft Edge is another web browser that offers only the basics of private browsing: it protects you against other people using the same computer knowing what you do online. It does not protect you against anything else.

Microsoft Edge InPrivate window

Internet Explorer can offer tracking protection and ad blocking if you configure it manually

Internet Explorer is an old browser, and most people make fun of it. You would not expect it to perform decently, would you? We were surprised to see that you can get tracking protection in Internet Explorer as you do in Firefox. However, the catch is that it is not enabled by default and, once enabled, you need to configure it manually, like this: Set up your own AdBlock in Internet Explorer. Another issue with it is that it allows users to reopen closed tabs, even in its InPrivate browsing mode.

Internet Explorer Reopen closed tab option in an InPrivate window

Therefore, if you forget one InPrivate tab open, someone else can restore your closed tabs and learn what you were doing online.

Opera is the best at private browsing if you enable two features

Opera was a refreshing surprise, and it has built-in features that place it above others when it comes to private browsing. However, you need to enable its best privacy features manually.

First of all, when you open a basic private browsing window, it offers the same level of protection as Google Chrome and Microsoft Edge. However, you also get a VPN button on the left side of the address bar. Also, Opera encourages you in its description of private browsing to enable VPN. If you click the VPN button, you are automatically connected to Opera's best VPN server, depending on your location. This way, your ISP and the organization your computer's in, should not know what you are doing online. Also, advertisers might treat you like another user, from another location.

VPN turned on in Opera Private browsing

If you want ad blocking and tracking protection, you can get that too, because it is built into Opera. However, it is not turned on by default. Click or tap the big O button in the top-left corner and go to Settings. The first setting is "Block ads." Check this box and choose the tracking protection options that you want to use. Once you do these two things, you get the most private browsing a web browser can offer, using only built-in tools and features.

The ad blocking features from Opera

We appreciate what Opera has to offer. However, other users may agree with us when we say that these two features should be enabled by default in Opera's private browsing mode.

NOTE: Some of you may say that the VPN offered by Opera is just a proxy-based VPN that does not encrypt your entire traffic. You might even say that it does not match the quality and anonymity that a real VPN solution offers. You would be right, but even so, it is more than what the other major web browsers offer, and it delivers better privacy when trying to browse the web privately, in comparison to other browsers.

What is your opinion about private browsing and what all browsers offer in this regard?

Now you know what private browsing is, what it does and what it does not do. You also have a comparison of the different private browsing modes that are offered by all the major web browsers. We are curious to know what is your view on this subject and what you think about our analysis. Comment below and let's discuss.