But, for online ads, we can switch things up.

Online ads can use geographic targeting and cookies to target their messages so you see the right ad at the right time.

Ad servers can deduce a user's geographic location by their IP address, which is like a zip code for your computer.

For example, by knowing your IP address, advertisers can serve an offer specific to your area.

Ad servers also recognize users based on cookie information.

You may see more relevant ads based on prior visits you've made to an advertiser's site.

Say you've just been eyeing a pair of super cool kicks on a company's website.

Later in the day, you might see an ad from that same company where they're offering free shipping.

Free shipping sounds great, but... let's talk about those cookies.

Cookies are text files assigned to your browser once you've visited a website.

When you go back to that website, it'll see that your browser has the cookie and will read it.

The cookie helps the site recognize your browser, and will restore any information you might have entered before.

You can see examples of cookies in action if you return to a site and don't have to sign in again.

Or when you return to a retail site to find your items patiently waiting for you in your shopping cart.

These are examples of first-party cookies ⏤ cookies set by the site that you're on.

It's important to keep in mind that cookies are anonymous.

The text file associates a random unique number with the computer and browser.

So, if you use different devices or browsers to visit the same website, each browser will have a different cookie.

There are also third-party cookies.

These are used by ad servers.

Online ads use third-party cookies to recognize the same user across multiple websites.

That free shipping ad we mentioned earlier? That's an example of third-party cookies at work.

When you went to supercoolkicks.com to check out those shoes, they allowed their ad server to set a third-party cookie on your browser.

So, when you visited that news site later in the day, the ad server recognized their cookie and used the information in it to show you that offer.

Geographic targeting and cookies help advertisers show relevant messages to potential customers,

and they sometimes even help customers get deals on stuff they buy online.