Since 2008, January 28th has been set aside for Data Privacy Day. The goal: “to create awareness about the importance of privacy and protecting personal information.”

It’s the perfect time to take a look at one privacy feature that’s right in front of you: your web browser’s private browsing mode. Just what is it that makes private browsing private? Let’s take a look at the major browsers and see.

Google Chrome

Google Chrome calls it Incognito Mode, and you can tell you’re using it by looking for the “secret agent” icon in the top left corner of the window. Chrome also shows you a big, bold new tab page when you open an Incognito window. That’s it at the top of this post.

In Incognito Mode, Chrome won’t keep track of the pages you visit, the data you enter into forms, or any searches you submit. It won’t remember what files you download, but those files will stay on your computer after you close the Incognito window. You’ll have to manually delete them if you want them gone. The same goes for bookmarks you create.

Internet Explorer and Edge

Internet Explorer and Edge feature InPrivate browsing. The same caveats apply: temporary internet files like cookies, browsing history, form data) are not saved. Downloaded files and bookmarks stick around even after you close the InPrivate window.

Microsoft’s browsers also disable any third-party toolbars you might have installed when you start an InPrivate session.

Firefox

Mozilla welcomes you to Firefox’s Private Browsing mode with a nice, clear explanation of what it does and doesn’t do. The list pretty much lines up with Chrome, IE, and Edge: browsing/search history and cookies are not saved, downloads and bookmarks are.

Mozilla also gives you an additional setting that can make Private Browsing a little more private:tracking protection. Turn it on and Firefox will attempt to prevent sites from gathering data about your browsing habits.

Safari

Safari’s private browsing mode also removes temporary files when you close the window. Browsing history, form data, and cookies are all wiped by default.

Opera

Opera is noteworthy because its private browsing mode offers one truly unique feature. You can turn on a VPN connection to add another layer of secrecy to your browsing activities. It’s not a bulletproof VPN solution and it still doesn’t keep your activities totally private, but it does provide additional protection.

It may also technically be considered a proxy and not a true VPN, but that’s a discussion you can leave to the more technically-inclined folks.

Beyond the VPN, Opera’s private browsing mode works like Chrome’s.

How Private Is It?

The short answer is not very, regardless of which browser you use. On the computer, tablet, or phone you’re using, yes, your temporary browsing data is removed.

It’s still very possible to see what you’ve been doing. Routers, firewalls, and proxy servers could be keeping tabs on your browsing activities, and private browsing mode won’t get in the way of that.

If you’re thinking private browsing will keep your activities hush-hush at the office, for example, you’re probably wrong.

So Why Use Private Browsing Mode?

There are plenty of valid reasons to use private browsing mode. You can use it to log into multiple email, social network, or bank accounts at the same time. Trying to surprise someone with a gift or vacation plans? Private browsing will help keep your activities quiet.

Ever used a computer in a hotel lobby or library to access your accounts? While always carries a certain amount of risk, private browsing can reduce it. If you have to check your email or sign into Facebook, it’s still a good idea to use private browsing to make sure your activities vanish when you close the window.

Can You Ever Keep Your Browsing Completely Private?

You’ll need additional apps. The TOR browser and a VPN connection to a trustworthy provider — especially used together — will offer you much better privacy protection. Even then, it’s best to assume that your browsing still isn’t totally private. TOR users have had their identities exposed in the past and VPN providers aren’t necessarily beyond the reach of law enforcement.