# Cookies, Personalization and Privacy: A Cybersecurity Expert‘s Perspective on Customized Content in 2025 - Canonical: https://33rdsquare.com/cookies-personalized-content/ - Published: 2024-02-09 - Author: Bruce Schneier - Categories: [Security & Privacy](https://33rdsquare.com/category/security-privacy/) --- Web personalization has become ubiquitous in recent years, with an estimated 92% of websites now using cookies to track visitors and tailor content to their interests.[^1] For many internet users, it‘s a familiar experience: you search for a product or click an ad, and suddenly your browser is full of related content and offers. But have you ever stopped to wonder exactly how websites seem to read your mind? The answer lies in cookies—small text files that websites place on your device to remember you and your preferences. Specifically, _personalization cookies_ are what enable sites to track your browsing activity and use those insights to show you targeted content.[^2] By logging pages you visit, links you click, searches you perform, products you view and purchase, and other details about your online behavior, these cookies help sites build detailed profiles about your interests. On your first visit to a website, it assigns you a unique ID number that gets stored in a cookie in your browser. Then, as you browse, the site collects data about your activity and ties it to your ID.[^3] This typically includes: - Pages visited - Links clicked - Searches performed - Products viewed/purchased - Ads clicked - Device details (e.g. location, browser, OS, screen size) Using techniques like cookie syncing, websites can even share this data with their advertising partners.[^4] So if you click an ad on one site and later visit the advertiser‘s site, they can recognize you and access your profile. Over time, websites amass a substantial amount of data about each visitor‘s interests and behavior. When you return to a site you‘ve visited before, it checks for your cookie and uses your ID to look up your profile in its database. The site‘s algorithms then instantly process all that historical data to generate hyper-personalized content just for you.[^5] Common examples of personalized content include: - Product recommendations based on past purchases or views - Articles similar to ones previously read - Ads matching browsing interests - Location-based suggestions using IP address - Pricing optimized based on your profile[^6] - Political messages microtargeted to your interests[^7] The result is a highly customized experience that feels tailored to your unique needs and interests. Personalization benefits both consumers and websites: users get more relevant content and offers, while websites boost engagement, conversions, and revenue. Studies show personalized content can increase conversions by up to 20% and revenue by 15% compared to generic content.[^8] However, this comes at a cost to privacy. Many web users are uncomfortable with the idea of cookies tracking their every move online and compiling detailed behavioral profiles. A 2022 survey found 74% of US consumers are concerned about the privacy implications of personalized ads.[^9] And according to Pew Research, 79% believe the potential risks of data collection by companies outweigh the benefits.[^10] There are also security risks associated with cookies. Attacks like cross-site scripting and cross-site request forgery can allow hackers to steal cookies and hijack user sessions.[^11] And techniques like zombie cookies and respawning make some cookies nearly impossible to delete.[^12] In response to these concerns, data privacy regulations like the EU‘s GDPR and California‘s CCPA now require websites to obtain affirmative consent before using cookies for ad personalization. But in practice, many cookie consent prompts use dark patterns to nudge users toward agreeing.[^13] A 2022 analysis of the top 250 websites in France found 62% used some form of dark pattern to improperly influence users‘ choices about cookie tracking.[^14] Looking ahead, the push for greater online privacy may lead to new alternatives to third-party cookies. Google plans to phase out third-party cookies in Chrome and replace them with its Privacy Sandbox, which uses federated learning and differential privacy to enable interest-based advertising without individual tracking.[^15] Apple and Mozilla have already blocked third-party cookies by default in Safari and Firefox. However, these changes won‘t spell the end of personalization. Websites are already adapting by using techniques like browser fingerprinting and collecting more first-party data.[^16] A 2023 survey of marketers found 85% plan to increase their use of first-party data for ad targeting as cookies decline.[^17] Ultimately, the future of personalization will likely be a mix of new privacy-preserving technologies and first-party data strategies. Websites that prioritize transparency about data practices and give users meaningful choices will be well positioned to build trust. But the drive to deliver ever-more personalized experiences will remain—it will just have to evolve within a more privacy-conscious world. [^1]: [The State of Web Personalization in 2024](https://www.zogby.com/2023-state-of-web-personalization) [^2]: [HTTP cookies – Wikipedia](https://en.wikipedia.org/wiki/HTTP_cookie#Tracking) [^3]: [How Cookie Tracking Works – CookiePro](https://www.cookiepro.com/knowledge/how-cookie-tracking-works/) [^4]: [Cookie syncing – Cookiepedia](https://cookiepedia.co.uk/cookie-syncing) [^5]: [How Personalized Recommendations Work – Built In](https://builtin.com/machine-learning/how-personalized-recommendation-system-works) [^6]: [Pricing & Personalization – Profitwell](https://www.profitwell.com/recur/all/dynamic-pricing-personalization) [^7]: [Voter Microtargeting With Cookies – Brennan Center](https://www.brennancenter.org/our-work/research-reports/microtargeting) [^8]: [The ROI of Personalization – McKinsey](https://www.mckinsey.com/capabilities/growth-marketing-and-sales/our-insights/the-future-of-personalization-and-how-to-get-ready-for-it) [^9]: [Cheetah Digital Consumer Trends Index 2022](https://www.cheetahdigital.com/press-releases/75-percent-consumers-say-degree-personalization-brands-borders-creepy) [^10]: [Americans‘ Views on Data Privacy – Pew Research](https://www.pewresearch.org/internet/2019/11/15/americans-and-privacy-concerned-confused-and-feeling-lack-of-control-over-their-personal-information/) [^11]: [OWASP Top 10 Web Application Security Risks](https://owasp.org/www-project-top-ten/) [^12]: [Zombie cookies – Wikipedia](https://en.wikipedia.org/wiki/Zombie_cookie) [^13]: [Dark patterns after GDPR consent pop-ups](https://fil.forbrukerradet.no/wp-content/uploads/2018/06/2018-06-27-deceived-by-design-final.pdf) [^14]: [Consent Issues on Top French Websites](https://arxiv.org/pdf/2204.13111.pdf) [^15]: [Google‘s Privacy Sandbox – web.dev](https://web.dev/digging-into-the-privacy-sandbox/) [^16]: [State of Personalized Advertising 2022](https://www.roirevolution.com/blog/2022/08/state-of-the-industry-future-of-personalized-advertising/) [^17]: [Merkle‘s 2023 Customer Engagement Report](https://www.merkleinc.com/thought-leadership/white-papers/2023-customer-engagement-report) --- Source: [Cookies, Personalization and Privacy: A Cybersecurity Expert‘s Perspective on Customized Content in 2025](https://33rdsquare.com/cookies-personalized-content/)