I am creating an app that requires to know if the visitor visiting the app is a unique visitor or an already visited visitor. I know we could persist a cookie on the visitor's computer to know identify this. What I would like to understand are the different other ways that can be used to know to keep track of unique and existing visitors? How does Google Analytics know whether it is a unique visitor or an existing visitor?Can I use browser fingerprinting (https://panopticlick.eff.org/) to know unique visitors/ existing visitors?
How to keep track of a unique and an existing visitor
google analytics;tracking;analytics;visitors
Unique visitors are identified by GA using the __utma cookie set by analytics. Here is a official article on Cookies used by GA. You could refer to these cookies by reading them using your server side script.If you have a login system in your app, you could try setting a customvariable as the user id (which would be unique). Here is the document on Custom Variables in Google Analytics.