This has probably happened to you: You ‘Googled’ a number of sites to price computer software. Then, you visited a site about something completely different, but the ads were for—surprise!—new computer software. This seems strange, right?

Another scenario you might recognize is that you enter a keyword you’re targeting into a Google search to see how you rank and find that you’re number 1 on the list! But when you check the same keyword later, without logging in to your Google account, you discover that you’re not listed in the results at all.

What exactly is going on?

It may seem like a coincidence, but the truth is that privacy advocates have been after Google for years, claiming that the Internet juggernaut has crossed the line on numerous occasions in the way it obtains and stores information about its users.