I'm not a RoboHelp Server user, but I believe it only offers reporting on Topic popularity. To report to the user level would require each user to authenticate before using the help system. I'm sure in some cases they do, but I don't believe RoboHelp Server offers that level of granularity and detail.
If it does, I'd be shocked.
Helpful and Handy Links
I don't know where you are based but check with your HR people. In the UK I believe they have to be involved in such tracking for legal reasons. I don't have details so I am just saying you need to check out going down to user level.
See www.grainge.org for RoboHelp and Authoring tips
To add to what Peter and Rick have already added you should be able to use some third party tool to do what you require if the user level stats are recorded. We are planning on using the RH Server output in a secure environment. The idea is that the user logs on to the application using a userid and password and from there accesses the help. As they do so, their userid and password is passed to the server to authenticate access. If they access a URL from outside the application, they will be asked for a userid and password. All of this is being done outside of RH server and whilst we are not recording the indivudual access requests it would seem impossible to adapt our method to do so.
Read the RoboColum(n) for mutterings on RoboHelp, Technical Communication Suite and technical communication.