How ads follow you around the internet

This video outlines how cookies work and how they’re being used, along with some context from Lou Montulli, who invented cookies in the summer of 1994 while working at Netscape.

Cookies do improve our online experience. In fact, without cookies, the internet we know couldn’t exist. But they impose privacy concerns, as well, which has become even more of a topic in recent years, although even in the 90s it was a concern among a smaller segment of the overall population.

A browser cookie is a small piece of code stored on a user’s computer by your web browser to access websites. Cookies were designed to be a reliable mechanism for websites to remember 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 perform essential functions. Perhaps most importantly, authentication cookies are the most common method used by web servers to know whether the user is logged in or not, and which account they are logged in with. Without such a mechanism, the site would not know whether to send a page containing sensitive information, or require the user to authenticate themselves by logging in.

The security of an authentication cookie generally depends on the security of the issuing website and the user’s web browser, and on whether the cookie data is encrypted.

Security vulnerabilities may allow a cookie’s data to be read by a hacker, used to gain access to user data, or used to gain access (with the user’s credentials) to the website to which the cookie belongs.

Furthermore, and most pertinent to this article, revenue from advertising is a strong incentive for companies to track online behavior. Brands want to sell products by serving ads. Publishers, who create content, want to make money by serving ads when visitors are on their site. And middlemen are in the business of ensuring the ads from the brands are delivered to the right people.

In other words, there’s a lot of vested interest in maintaining cookies. So, expect ongoing tension between privacy concerns and the big business of online advertising.