The creative-yet-creepy forms of online tracking have become so sophisticated that billions of Internet users have likely triggered the tracking without ever knowing it. But “there is hope,” experts say.

One especially popular program — called canvas fingerprinting — commands user’s computers to draw a hidden image when it visits particular sites. The canvas image created by the process contains a unique set of data that differentiates from millions of other users — much like a human fingerprint, hence the moniker.