Whether you’re secretly searching for a gift for someone who uses your computer, planning a surprise event or just looking at websites you’d prefer to keep to yourself, there are plenty of reasons to want to keep your web history in the shadows.

There a few different ways of doing this, and they all depend on who it is you want to hide your history from. But here’s the thing: The websites you visit in private browsing modes can still be tied back to you. Even if the people on your computer can’t see which websites you’ve been visiting, your Internet provider and the websites you’re visiting can. Here’s how it works.

What private browsing modes do

Safari, Google Chrome, Firefox,Opera and Internet Explorer all have private browsing modes you can use to make sure the websites you visit don’t appear in your browsing history. Typically, your browser will record a running log of each website you visit and store information about what you entered into search and information forms on websites.

So, if you found an awesome T-shirt on an online store, but can’t remember which store it was or what you searched to find it in the first place, your browser will store that information so you can use it later.

Your browser will also store cookies from websites, which are small files of data that help tailor a website to you and your computer. Whenever you go to a website that already has you logged in, remembers what you were last looking at or displays ads that eerily fit what you’ve been searching for, that’s a cookie at work.

Read more and about what private browsing modes don’t do…