This is done via StatCounter, a third-party service.
Cookies are used only to determine whether you are a first-time or returning visitor to the website and to count visits and page views to the site. No personal or confidential data is stored in the cookie. The information these cookies collect is anonymous and used only to generate visitor ‘stats.’
Cookies are very small files of data which are stored on a user’s computer. They are not executable pieces of code and cannot be used to infect a computer with malware or a virus.
In other words, cookies are how, for example, Amazon ‘remembers’ you when you revisit the site.