The importance lies in the determination of the visitors perception of the project and how – and into which direction – the network or etailing site needs to develop if a certain site/section or piece of content is percieved as uninteresting or even neglected. 
The problem the personal profiling though. While the social networks have a pretty easy time because they hold tons of information about a person etc., the etailing platforms can only rely upon the information given by the customer in the past. And let’s be honest: while we spend hours and hours detailing our profile on social networking platforms we get sceptical when a commercial platform asks us for a our date of birth or associated, “intimate” information. 
The metrics used are a combination of those in every above standard web analytics software plus the data a platform holds about it’s users. 
Hope I was able to help and feel free to call me if you need any more information.

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