In terms of search engine marketing, this is the act of getting a search engine to record content for a URL that is different than what a searcher will ultimately see. It can be done in many technical ways.
To understand unique visitors first we understand what are hits, visitors, and pageviews.
Hits: All file sent to a browser by a web server is called as an individual hit.
Page views: A page view is counted as each time a visitor views a page on the website, despite of how many hits are generated. The pages on any websites are comprised of files and every image in a page is a separate file. When a visitor comes across at a page (a page view) they may see several images, graphics, pictures etc. and create multiple hits.
Visit: A visit occurs when someone or any robot visits the site. It includes one or more page views or hits. A one visitor can make multiple visits to the site.
Visitor: A visitor is a human and the action performed by him is ‘human’ events; this is because only humans use browsers to navigate the internet.
Unique Visitors: Unique visitors are defined as actual users of any website. Unique visitors are usually counted by address and through user agent string. The number of unique visitor is normally much lower that hits to the web site. Hence, unique visitors are those who visit a Website more than once within a particular period of time.
Software’s that are capable to track and count web site traffic can differentiate between visitors who only visit the site once and unique visitors who come back to the site. Unique visitors are dissimilar from a site’s hits or page view, which are measured by the number of files that are requested from a site — unique visitors are calculated according to their distinctive IP addresses which are like online fingerprints and unique visitors are counted only once no matter how many times they visit the site.
Software that monitors site traffic can make a distinction between visitors who only visit the site one time and unique visitors who revisit to the site. Unique visitor data are measured to be the most accurate measurement of a Website’s popularity because they reproduce the number of people who want to be there relatively than those who have arrived there by accident. Unique visitors are measured, but their IP address no matter how many times they visit the site, they are only counted once.
The figure of Total Visitors to a site divided by Unique Visitors consequences in the derived statistic Average Sessions Per Unique Visitor which tells a publisher how many times each Unique Visitor came to the site on average in the time border of the report.
Unique Visitors value is most precisely measured in two ways with current technology: