Online shopping is convenient, but it comes at a privacy cost that most people don't think about. Every purchase generates data: what you buy, when you buy it, how much you spend, what you looked at but didn't buy, and more. That data is used to build detailed profiles of your behavior — and it's often shared with parties far beyond the shop you bought from.
What online shops collect about you
When you shop online, retailers collect significantly more than just your shipping address and payment details. Modern e-commerce tracking captures your browsing path through the site, which products you viewed, how long you spent on each, which items you added to cart and then removed, and the precise timing of all of this.
This behavioral data is analyzed to understand your shopping patterns, predict future purchases, set personalized prices, and build a profile that can be used for targeted advertising both on the retailer's own site and across advertising networks.
Your email address as the link between online and offline
When you provide your email address at checkout or sign up for a loyalty program, you create a link between your online behavior and your identity. Retailers use this to match your online browsing with in-store purchases, and to share your data with advertising platforms that can target you across other websites and apps.
This is why you might search for a product on one website and then see ads for it across unrelated sites and on social media. Your email address is the thread that connects your activity across platforms.
Using a disposable email at checkout (for orders where you don't need account access) breaks this connection. The retailer can send you a receipt, but they can't match your purchase to your broader advertising profile.
Third-party tracking on retail sites
Most e-commerce sites run dozens of third-party tracking scripts from advertising companies, analytics providers, and data brokers. These scripts run in the background while you shop, collecting behavioral data that's sent to the third-party companies regardless of whether you make a purchase.
Using a browser with tracking protection enabled — Firefox with Enhanced Tracking Protection, or Brave browser — blocks many of these scripts. Browser extensions like uBlock Origin also provide effective blocking.
Practical steps to shop more privately
A few habits make a meaningful difference. Use a credit card rather than a debit card for online purchases — credit cards offer better fraud protection and an extra layer between merchants and your bank account. Use your browser's private or incognito mode for browsing products before buying, as this limits cross-site tracking through cookies.
For guest checkout rather than creating an account, use a disposable email for the order confirmation. This gets you the receipt and tracking information without creating a permanent profile.
Be selective about loyalty programs. The discounts they offer are funded by the value of your data. If you use loyalty programs, keep them limited to shops you use very frequently, where the data tradeoff is worth it.