Researchers at Germany's University of Leuven have studied the internet's top 10,000 websites and discovered that almost 1.5% of them are tracking users without their consent.
They also identified 16 new providers of device fingerprinting. Only one of these had been identified in prior research.
Hidden scripts are used to extract device fingerprints, circumventing the legal restrictions on the use of cookies and do not track headers.
Device fingerprinting involves the collection of information on the device being used and the combination of this information can be so unique it acts as a digital fingerprint.
Read more about the research here.