Did you know that every time you go online, your web browser leaves a massive trail of information behind?

Anyone with access to your computer could review this information to learn a lot about your habits. What's more, your browser happily reports more than you think to the websites you're on.

Just how bad is this? Let's take a look at the various details your browser reveals about you.

History and Cache

Here's an obvious one. As you probably know, most browsers include a History function that collects every single page you visit. If you don't clear it, this information is freely available for anyone to see.

This lets others see what websites you visit, how frequently, and follow your "train of thinking" when you were browsing. That's a lot of information you probably don't want to share.

browser history and cache

If you don't thoroughly clean your browsing data, you might also leave cache information behind. Cache refers to bits of information your browser downloads so that it can quickly display them next time you visit, thus speeding up your browsing. Someone typing chrome://cache into Chrome or about:cache into Firefox could review all current cache entries.

Cookies

While your history is a simple list of links you've clicked, cookies have more nefarious uses. Of course, not all cookies are bad. Checking the Keep me signed in box and setting preferences for a website wouldn't work without cookies. But click around a few popular websites, and you'll pick up boxes' worth of cookies.

These follow you around your web travels and share your browsing data with advertisers in order to show you more relevant ads. This is why you see ads for a product you just viewed on Amazon when you're reading a news article.

browser cookies

Clearing cookies temporarily wipes this tracking, but they build up again when you start browsing. Thus, cookies serve as a giant map of your web journey and show what you're interested in. And that's not even considering the more dangerous supercookies.

Bookmarks

Have you ever considered the information someone can glean about you just from your bookmarks?

Take a look at your bookmarks bar, and you'll probably see shortcuts to your financial websites, favorite news pages, and other telling info. If someone knows that you use Bank of America and your email address, they would be one password theft away from breaking in. Seeing your favorite news sites gives an idea of your views and beliefs. How about seeing a bookmark to a dating website, revealing that you're (hopefully) single?

bookmarks and bookmarks toolbar

This goes for your homepage, too. Is your start page potentially embarrassing? What if you have your browser set to open your tabs from last time and that accidentally reveals something?

True, knowing that you like to read NPR isn't a compromising fact on its own. But seeing the websites that matter most to you is one more piece of information that your browser reveals to anyone who accesses it.

Extensions

So far, we've only discussed what your browser alone can reveal about you. Add in extensions, and you've got a whole new set of problems.

Most browser extensions require invasive permissions to work properly. Many of them are legitimate, but not all. We've collected lists of extensions you should not install due to known privacy violations like selling your browsing info. Because most of these are available for free, they have to make money somehow. Even once-legitimate extensions can sell out to spammers and start leaking your information.

Saved Passwords and Autofill Info

Most browsers offer to save your passwords, address, and even your credit card. While this is convenient, you guessed it: your browser doesn't always keep this private.

Using your browser, someone could use the autofill to reveal your address and a lot more. If you don't keep your passwords saved in a secure manager, someone could peek at them when your browser fills them in.

Technical Information Reported to Sites

Let's say you clear your history regularly, don't use bookmarks, have no extensions, and haven't saved any autofill information. You're all clear then, right?

No. Your browser still reports a fair amount of information to every website you visit. Visit Webkay for one example. This website knows your approximate location, OS and browser version, basic info about your CPU and GPU, your download speed, and what websites you're logged into. That's quite a bit of info that any website can use without your permission.

computer hardware details

Click is another scary proof-of-concept. This tool shows how your browser reports where your mouse it moving, when you're leaving a site, and exactly when you've interacted with the site. Complete with audio, you'll feel like someone is really watching you.

Click tool in relation to browser privacy

Social Sites and Google Tracking

Here's more good news: Google, Facebook, and other massive entities track you all over the web. If you're logged into a Google account, Google keeps track of every website you visit. Facebook and Twitter use those social sharing buttons to keep an eye on what you're doing, too.

But even if you aren't logged into Facebook, it still tracks you. Google keeps track of what every user clicks even if you aren't logged in.

These companies make billions of dollars in advertising. It's in their best interest to figure out what you like and show it to you, thus the incessant tracking.

What About Incognito and Private Browsing?

You might think that you've defeated all this potentially incriminating information because you use incognito or private browsing. Unfortunately, while incognito mode does prevent your browser from saving history, it does little else to protect you.

Someone could snoop on your private browsing with several methods. Your ISP still sees what you're doing unless you use a VPN. And going incognito doesn't stop your browser from reporting information to websites or prevent tracking.

While incognito mode is a useful tool, it's far from a solution to the problem of browsers leaking information.

How Can I Prevent This?

While you can't stop your browser from sharing every bit of information about you, you do have ways to limit what it shares.

A great start is installing an anonymous web browser built around protecting privacy. Unlike mainstream options, these have a goal of keeping you as safe as possible. If you can't switch your entire browser, you can still get some benefit by installing some privacy-protecting apps.

And if you're all-in on online privacy, check out our guide to avoiding internet surveillance.

Is Your Browser Sharing Too Much?

From minor incidental information to major trends and interests, your web browser reveals a lot about who you are and what you do. It's scary to see all this in one place, but you thankfully have options for combating it.

Unfortunately, your browser information is just one of the many ways you're being exploited every day.

What type of information was the most shocking to you? Do you use any privacy measures to stop your browser from sharing information? Tell us in the comments!