Long story short: based on their IP address and other proprietary market signals.
It's important to note, that we do not identify individual visitors (people), only companies and other organizations (such as universities).
When people visit a website, Snitcher captures their IP address and runs a series of checks. Starting with our existing database of companies, then through the latest market signals to ensure the accuracy of the identification.
We then enrich the company identified with fresh firmographic fields such as industry, size, location etc before presenting the company has visited your website.
Lastly we include detailed information about what they have done on your website, as well as how they've found your site in the first place is included.