Facebook, just like Google or for that matter any company serious about doing business on the web, watches its users. It watches them closely and tries to follow their footprints across the web because if it understands users well it can serve them advertisements that are more relevant. Depending on how your idea of privacy and convenience this can either be a good thing or bad.
But irrespective of what you feel about how Facebook watches, and its tracking of web users is fairly pervasive , there is one mistake that you make which helps Facebook track you better.
Those who know concepts like "cookies" understand that when they are logged onto a site, that site can often connect their online behaviour with their profile. Most people don't mind or care about it, but those who do often log out of the websites once they have finished their work there. This means, once that email is sent or the FB post is updated, the user logs out to minimise the web tracking.
Those who dont know what is "cookies" are in term of internet meaning, cookies is a small piece of data sent from a website and stored in the user's web browser while the user is browsing. Every time the user loads the website, the browser sends the cookie back to the server to notify the user's previous activity. Cookies were designed to be a reliable mechanism for websites to remember stateful information (such as items added in the shopping cart in an online store) or to record the user's browsing activity (including clicking particular buttons, logging in, or recording which pages were visited in the past). Cookies can also store passwords and form content a user has previously entered, such as a credit card number or an address.
But when it comes to Facebook, this is where people make a mistake. The issue is with the Facebook login API, that is used by hundreds of websites. Web users use this API all the time even when they are not using Facebook. For example, you are on Quikr or OLX, trying to sell something. Instead of creating an account with OLX, you use Facebook to log into the network. You get in, place an ad or respond to an ad and then log out of the OLX.
Now, you would assume that you have logged out of Facebook's network. But no. Logging out of OLX, even if you are using Facebook ID to log in, only logs you out of the OLX. On the computer, you continue to be logged into the Facebook network. So for example, after logging out of the OLX if you open Facebook, you won't have to log into the social media site. You will directly go to your timeline.
What this means is that once you have logged into a third-party website using Facebook ID, you not only have to log out of that website but also need to open Facebook and then log out again. Only then you will be out of Facebook network. If you just log out of the third-party website, Facebook would continue to identify your browsing session and probably connect it to your profile.
Even when you logged out, the cookies placed by companies like Facebook and Google track browsing sessions. But in these cases, they can't explicitly associate the browsing data with a particular profile.
Now, Facebook here is definitely not wrong. Some people don't even mind tracking of web sessions because they get to see more relevant ads. But it sure looks like somewhat disingenuous that it is not made clear to users that they would have to log out twice to get out the Facebook network.
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