I do purchase information on who ( Who refers to the ISP provider information, much of this is visits by"Bots" etc which are dead programs as opposed to live people using their computer.) has visited Planette Earth which gives me the following information on visitors:
Returning Visits - Based purely on a cookie, if this visitor is returning to the website for another visit an hour or more later
First Time Visits - Based purely on a cookie, if this visitor has no cookie then this is considered their first time.
Unique Visits - Based purely on a cookie, this is the total of the returning visits and first time visits - a total count of visits.
Page Views - The number of times a page has been visited.