Visitor Identification Techniques & Cookies
One of the challenges for Web Analytics solutions is how to define a session. Measuring a page view (or page impression) is easy and pretty accurate. However, in order to define a session, Web Analytics solutions need identifiers.
There are a number of user identification techniques available with varying degrees of accuracy. Obviously the most accurate measure is user authentication, by which users are asked to log in with a user name and password. However, this method of user identification is impractical and unnecessary for many websites.
Instead many websites use cookies (first or third party) for user identification purposes. Cookie-based sessionization could be considered as the next best option in terms of accuracy and reliability. Cookie deletion and blocking by the users, impeding the accuracy of this technique.
Web Analytics community has been debating the cookie issue for some time now and are in search of other means of accurate and reliability user identification on the web.