Its software tracks minute characteristics in typing patterns; for example, how long a person presses on each key. Scout claims that everyone has a personal typing rhythm that can be quickly differentiated.

The company says this “biometric signature” can be used to eliminate errors in user counting, such as in instances where more than one person shares a website account.

Scout set about researching this by analysing more than 20m visits to various paid-for sites. The company determined that those 20m visits originated from nearly 600,000 unique devices – work or home PCs or mobile phones.

“Further correlating the biometric signatures from the visits, Scout Analytics identified more than 175,000 unique individuals – approximately 45,000 of whom were unlicensed,” the company said.

Using traditional cookie-based measures alone would have overstated each websites’ user counts by two-to-four times, said Scout.