Returning User Metric Definition
The Returning User Metric tracks people when they return to your website more than once. This metric allows analyst and digital marketers to see how effective they are at building and retaining an audience online and retaining their attention. This relates to your websites stickiness and how likely other users are to come back.
As you monitor your web analytics over time keep an eye on the percent of users who are returning. This should continue to increase and is a great indicator of how sticky and engaging your content or product is.
Returning User Metric Challenges
Most major web analytics tools like Google Analytics, Mixpanel, Heap, Kiss Metrics and so on track web users at the device level. So if someone visits on their desktop today and their mobile phone tomorrow then the web analytics tool doesn't know this is the same user and therefore not a return user.