Unique visitor is a term used in web analytics to measure the number of individuals who visit a website or web page during a certain period of time. The unique visitor concept aims to identify and quantify every individual who accesses a website, even if they visit the site multiple times in the same time period.
Example :
10 people in 1 WIFI visiting your link or microsite will count: 1 unique visitor and 10 visitors
3 people in different connections (both cellular and WIFI) will count: 3 unique visitors and 3 visitors
Because if someone visits your linked site or microsite again, the system will check if the unique information exists, and if so, the visitor is not counted as a new unique visitor.