Unique visitors refer to the number of distinct individuals requesting pages from a website during a given period, regardless of how often they visit. This metric is crucial in understanding the actual reach of a website or the breadth of its audience. When tracking unique visitors, each visitor is counted only once, even if they return multiple times within the reporting period. This count is typically determined by tracking cookies or login information that can identify a user across multiple sessions. It’s an important indicator for marketers as it helps to gauge the size of the potential market, the effectiveness of marketing campaigns in attracting new audiences, and the website’s ability to retain visitors. Unique visitor data is also valuable for advertisers who want to understand the exposure and impact of their online advertisements.