If you’re like most people, then you log into Facebook or Google a few times per day. Or maybe you’re constantly logged in. Whatever the case may be, a new security report has emphasized the importance of clearing cookies before you log into online services like Google or Facebook.
Why is deleting your cookies so important? Let’s find out.

Facebook and Google Collect Anonymous Data About You All The Time

Every time you visit a site with a Google AdSense advertisement, Google makes a note about you. That note looks something like this: Anonymous User #13294123 was spotted on a video games website searching for GTA V cheat codes.
At this point, you’re just an anonymous internet user. Google can’t identify more about you than the fact that you were browsing a website with Google AdSense at a certain time and place.

Facebook works in a similar way: it logs a cookie every time you visit a site with a Facebook widget. Facebook widgets include “like” buttons – like the ones where everybody’s faces show up in a box below the like button.
Facebook knows when you visit these sites and, like Google, it makes a record in its history of you. At this point, you’re still just Anonymous User #13294123.
You might collect hundreds of such cookies during an average day browsing the internet. All of these cookies are anonymous, but Google and Facebook can still build a more complete profile of your activity.

What Happens When You Log In

When you log into Google or Facebook, you’re no longer anonymous: Google and Facebook are both instantly able to connect all the cookies you’ve collected to your account. Instead of being Anonymous User #13294123, you’re Ryan Smith from Los Angeles, California and you like video games, sports, and superhero movies.
All of the anonymous cookies you collected while browsing logged out are now connected directly to you – logged in.
The moment you log into Facebook or Google, they know significantly more about you than ever before. Basically, you’re making it easy for both of these online services to paint a more complete profile of your activity and interests – which makes delivering advertisements a lot easier.

Why This is Scary

Let’s say you like to visit a NSFW site after a long day of work. You take the time to log out of your Facebook and Google accounts before going to that site.

However, if that NSFW site has a Facebook share button or any type of Google ad, then a cookie will be placed on your computer. This cookie won’t be linked to you – unless, of course, you log into Facebook or Google at any point in the future without clearing your cookies.
Scary, right? Fortunately, Chrome’s Incognito Mode helps you avoid this because it doesn’t save cookies. However, a lot of people don’t use Incognito Mode 24 hours a day, 7 days a week.

How to Avoid Google and Facebook Tracking

There are some easy ways to prevent Google and Facebook from tracking you. The best way is to install certain extensions or plugins into your browser. Those plugins and extensions include:
–Self-Destructing Cookies for Firefox
–NoScript Security Suite for Firefox
–ScriptSafe for Chrome
Of course, you can also run programs like CCleaner before you log into Google or Facebook, or just clear cookies manually from your browser.
All of these plugins let you block third-party requests on websites you visit, preventing Google and Facebook from spying on you with cookies.