When you visit a website — just about any website — your visit is logged by third parties in a digital record. Advertisers use that information to make sure you see ads that are relevant to your interests. Content providers use it to make sure they’re posting videos and articles that you’ll want to watch and read.

Image: Pexels

Image: Pexels

For privacy reasons, the browsing data they collect is anonymized. Advertisers aren’t supposed to be able to target you with ads because they know you’re you. They’re supposed to deliver ads that fit the interests of some anonymous person who browsed a specific list of web pages.

According to a new study released by Princeton and Stanford researchers, however, it’s really not hard to figure out exactly who you are based on your browsing. All it takes is as few as 30 links shared publicly on Twitter or Facebook.

If you’ve done that, then the research team has a 50% chance of being able to tie your anonymous browsing to your social media account. The odds increase dramatically when they have better data to look at. They set up a test scenario with 374 volunteers who willingly handed over their browsing histories. The team was able to identify participants with a 70% success rate.

So while the browsing data you consent to transmit when you visit a website might be anonymous (or at least somewhat anontmous) when it’s collected, it doesn’t necessarily stay that way forever. If the Princeton-Stanford team was able to link anonymous histories to social media profiles, there’s a good chance that advertisers have figured out how to do it, too… or that they’re working on it right now.

There are steps you can take to protect your digital privacy, of course. Using a VPN can help, and so can the right privacy-focused apps and services.