Cookies are one of those integral technologies that we rarely think about, yet they play a vital role in our everyday web browsing experience. If I asked you to explain technically how cookies work, could you?
Don‘t feel bad if not, because cookies operate silently in the background to help websites remember you. But understanding exactly what cookies are, where they came from, and what they do can empower you to make informed choices about your online privacy.
Let me guide you through the sometimes confusing cookie landscape so you can master these ubiquitous bits of code!
Contents
The Humble Beginnings of Cookies
Today over 90% of websites use cookies to store data, with over 5 billion created per day, but they weren‘t always so popular.
Back in 1994, the "World Wide Web" was still in its infancy. Netscape engineer Lou Montulli was focused on solving a pesky problem – how could websites identify individual users that visited repeatedly? At the time, HTTP was stateless, meaning sites couldn‘t differentiate between first-time and returning visitors.
Montulli reminisced, "I had the idea that we could store a magic token on the user‘s computer that would be inserted on each request to the server. The server could then decode this token to determine who the user was."
And with that spark of inspiration, the internet cookie was born! Montulli coded up the first prototypes, and soon cookies were being used on Netscape and other early web browsers.
The technology quickly took off, as cookies offered an easy way for websites to identify users, personalize experiences, and keep them logged into accounts. Can you imagine the headache of having to re-enter your login each time you accessed a site?
An Inside Look: What‘s in a Cookie?
Simply put, cookies are tiny text files that websites store on your computer or other internet-connected devices. But what exactly is inside of one?
Each cookie typically contains:
- Name – A unique name assigned by the website
- Value – Data stored in the cookie, like a customer ID
- Expiration – How long the cookie will stay on your device
- Domain – The website domain that created the cookie
For example, say you visit example.com. When you view a page on their site, they may create a cookie named "UserPrefs" with your account ID as the value, an expiration of 1 year, and a domain of example.com.
Now whenever you navigate back to example.com, your browser will send along that UserPrefs cookie to quickly identify you!
Cookies range from a few hundred bytes up to 4KB. While that may seem tiny, websites can store dozens or even hundreds of cookies on your device that accumulate over time as you surf the web.
Breaking Down the Main Cookie Types
While all cookies operate similarly, there are a couple key types you‘ll encounter:
Session Cookies: Temporary Convenience
Session cookies only exist until you close your browser. They allow sites to link your actions during a single browsing session.
For example, say you‘re shopping on an ecommerce site. Session cookies keep track of the items in your cart as you browse, without requiring you to add them again each new page you visit.
Once you close the tab or browser, session cookies are deleted. This makes them less invasive than other cookie varieties.
Persistent Cookies: Your Online Memory
Persistent cookies have an expiration date and are saved on your device between browser sessions. They remember your site preferences and login details over long periods. For example, persistent cookies allow you to enter a site on Monday and still be logged in on Friday without re-entering your credentials.
Depending on the cookie, this persistence can be beneficial, like having your music app remember your favorite playlists. But it can also be used to track you between websites to serve targeted ads, which raises privacy concerns. More on that soon!
First-Party vs. Third-Party Cookies
Cookies are also categorized based on which website creates them. Understanding this distinction is key to managing your privacy.
First-Party: Essential Site Cookies
First-party cookies are created by the site you‘re currently visiting. For example, when you visit example.com, they can set cookies that help their site run properly or enhance your user experience there.
First-party cookies often store:
- Usernames and passwords for auto-login
- Shopping cart contents
- Site color or text size preferences
- Recently viewed pages or posts
By remembering your interactions with their content, first-party cookies allow websites to deliver a personalized, optimized experience each time you return. Most are harmless and even essential for websites to function.
Third-Party: Tracking Your Browsing Habits
Unlike first-party cookies, third-party cookies are set by domains other than the one you are visiting. These largely exist to track your online behavior for advertising purposes.
Here‘s how sneaky third-party cookie tracking works:
- You browse running shoes on an ecommerce site. It plants a third-party cookie on your device.
- Later, you visit a news site containing ads from the same third-party network.
- They serve you an ad for running shoes based on that earlier cookie, to target your interests!
This inter-site tracking happens behind the scenes on a huge scale. Third-party cookies are convenient for marketing, but raise considerable privacy concerns which we‘ll explore soon.
Weighing the Pros and Cons of Cookies
Depending on which kinds of cookies a site uses, they can offer advantages and disadvantages:
Potential Benefits of Cookies
- Remember login details and site settings
- Keep shopping cart contents between visits
- Enable basic site functions
- Provide personalized content recommendations
- Prevent fraud and abuse of site features
Potential Downsides of Cookies
- Allow inter-site tracking of your browsing history
- Raise privacy concerns around data practices
- Increase page load times and storage needs
- Pose security risks if malicious actors gain access
While first-party cookies tend to only enhance your experience, third-party cookies are where things get ethically murky…
The Controversial World of Online Tracking
Third-party cookies play a huge role in digital marketing by profiling your interests based on your browsing behavior across multiple sites. But how exactly does this work?
Essentially, advertisers partner with a frenzy of middle players to purchase access to your eyeballs. Here‘s a peek behind the curtain:
-
You browse for shoes on an ecommerce retailer. Their site plants a third-party cookie containing data about this interest.
-
Later, you load a news article containing an ad slot from an ad exchange like Google AdX.
-
In the milliseconds the page loads, the exchange holds a real-time auction for that ad space.
-
Data brokers bid your cookie data in the auction to target you with a shoe ad. Their bid wins.
-
The shoe ad displays, and if you click, the broker charges the advertiser, taking a cut for themselves.
This process repeats billions of times daily across the web. Although the ad may be relevant to you, many find this level of behind-the-scenes tracking and profiting off data creepy or unethical.
U.S. laws like GDPR and CCPA now require sites to explain their cookie practices and allow opt-outs. But the tracking continues on a massive scale.
So what can you do to take control of your privacy as you browse?
Tips to Manage Cookies Like a Pro
If you find yourself disturbed by the idea of cookies following your every move online, there are ways to fight back:
Adjust Browser Settings
All major browsers let you block third-party cookies. You can also clear cookies manually or set them to delete after each browsing session.
Use Privacy Extensions
Extensions like Privacy Badger, Ghostery, and uBlock Origin automatically block invisible third-party trackers that employ cookies to monitor you.
Try a VPN
A VPN routes your traffic through an encrypted tunnel to hide your IP address and prevent snooping on your web activity and cookies.
Opt-Out of Tracking
Some sites allow you to opt out of personalized advertising driven by cookies. Look for a "Do Not Sell My Personal Information" or "Ad Choices" link on pages.
Surf in Private/Incognito Modes
Chrome‘s Incognito and Firefox‘s Private Browsing modes prevent sites from installing cookies that track you long-term.
With some savvy settings adjustments and privacy tools, you can cut down on unwanted cookie tracking as you surf.
Cookies: A Love-Hate Relationship
As we‘ve explored, internet cookies provide both invaluable convenience but also raise concerns around online privacy.
While it can feel creepy being followed by cookies you never approved, remember that they also enable your seamless, personalized web experience. As with most technologies, the solution is not to eliminate cookies entirely, but to better understand how they work so you can manage your privacy.
I hope this guide has shed light on the secret life of cookies and how to keep them in check. Now whenever you‘re prompted to "accept cookies", you‘ll know exactly what‘s at stake and can make an informed decision.
So what will it be – accept or deny? The choice is yours!
