The term ‘uniques’ is often used in web analytics as an abbreviation for unique web visitors (i.e. how many unique people visited my site). The problem is that counting unique visitors is fraught with problems that are so fundamental, it renders the term ‘uniques’ meaningless. Firstly, cookies get lost, blocked and deleted. Research has shown that after a period of four weeks, nearly one third of tracking cookies are missing, which means the visitor will be incorrectly considered a new unique visitor should they return to the same website (see Accuracy Whitepaper for further reading). The longer the time period, the greater the chance of this happening, which makes comparing year-on-year data invalid for example. In addition, browsers make it very easy these days for cookies to be removed – see the new ‘incognito’ features of the latest Firefox, Chrome and Internet Explorer browsers. However, the biggest issue for counting uniques [...]