Updated

If you browse the Internet at all, you've run into targeted ads. You'll be looking at a product on one site, and then you’ll see an ad for it right away on another site. We've seen situations where a YouTube video will play an ad for the site you just opened in another browser tab. Creepy! Let's look at how it works and how you can stop it.

How it works

Most websites get their ads from ad networks. Each ad network puts a bit of code called a "cookie" on your computer. When you visit one of the member sites, the site recognizes the cookie and lets the ad network know where you are so it can send you personalized ads.

Even worse, the member sites share what you do on their sites to build a database of what you like and don't like, or even specific items you looked at. This makes it easier for the ad network to send you ads it thinks you'll click on.

Where it really gets scary is when you add Facebook into the ad network. Most websites have to figure out what you're thinking based on what you do. On Facebook, you tell it exactly what you're thinking.

Every "like," news story click, status update and photo caption you put in Facebook is a bit of information that advertisers would love to add to your file. And you'd be surprised how much money it can make them.

In 2013, online tracking and targeted advertising helped Internet advertisers rake in a staggering $42.8 billion. In 2014, that climbed to $49.45 billion – a 15 percent jump.

Naturally, you don't see a penny of it. You're just concerned with what happens to your information if a shady employee or hacker gets a hold of it. Or you just don't like the idea of being tracked.

How to stop the tracking

I've told you in the past how to opt out of Facebook's tracking and targeted ads though the ad network it's a part of, the Digital Advertising Alliance. But Facebook has now added this feature to its own settings.

To opt out of Facebook showing you targeted ads from other sites, or from seeing Facebook's ads on other sites, open your Facebook page and click the upside-down triangle in the upper right corner. Select "Settings" and then in the left-hand column select "Ads."

You'll see the new "Ads based on my use of websites and apps" setting. Click the "Edit" link, and then click the "Choose Setting" button and select "Off." You have to do this only once and it will apply to every gadget where you sign in with the same Facebook username.

Now, this won't stop Facebook from showing you targeted ads based on information it collects about you. But it won't get any of your information from its partners, and it shouldn't send any of your information to advertisers.

While you're in the ad settings area, you'll also want to change "Ads with my social actions" to "No one" so Facebook can't use your name in advertising. You can also change your preferences to control what kind of ads Facebook shows you.

This is good for dealing with targeted ads on Facebook, but it doesn't stop the rest of the 120 companies in the Digital Advertising Alliance from collecting your information and showing you targeted ads.

To make that stop, click here to visit the Digital Advertising Alliance's tracking opt-out tool. The tool will scan your computer to see what companies are customizing ads to target you. It can also tell if you've opted out of any online tracking for those companies in the past.

It's simple to choose a few companies and sites, like Facebook, where you don't want to see targeted ads. Or you can click the "Choose all companies" button at the bottom to opt out of targeted ads for every participating network member. Simple!

Now, opting out also doesn't stop these sites from collecting some information about you, but it does mean they won't share it with other companies. So you won't see ads in Facebook for things you've looked for on Amazon or eBay. It also limits what any one company potentially knows about you, and it keeps a single ad company from building up a detailed profile.

Because tracking is cookie-based, so is opting out. The site will put a cookie in your browser saying you don't want to be tracked. This means you'll need to run the tool in every browser you use so they're all covered.

There are still many companies online that don't participate in the Digital Advertising Alliance, so opting out won't change the way they behave. One way to put a stop to them is to disable third-party cookies in your browsers. You’ll just need to wait until after you run the DAA's tool so it works correctly.

Your browser isn't the only way advertisers can track you on your mobile gadget. There are also ads in apps. Click here to find out how to opt out of all targeted ads on Android and Apple.

You shouldn't be worried only about what advertisers and Facebook can see about you.

Strangers can find out more about you than you think if you have the wrong Facebook security settings. Click here to learn how to lock down your Facebook profile from beginning to end.

On the Kim Komando Show, the nation's largest weekend radio talk show, Kim takes calls and dispenses advice on today's digital lifestyle, from smartphones and tablets to online privacy and data hacks. For her daily tips, free newsletters and more, visit her website at Komando.com. Kim also posts breaking tech news 24/7 at News.Komando.com.