We are currently looking into setting up mobile access to our Service Desk Manager application and the question that came up first was; Will each analyst connecting via the mobile app take up a license?
Yes. A Mobile App. user who is an Analyst will consume a Licence.
The Mobile App. is no different to any other entry point to CA SDM.
You need to look at the Access Type assigned to the user to see whether they consume a Licence or not.
See this Knowledge Document along similar lines:
Mobile app, Employees got "The request requires us - CA Knowledge
Also note the comment on the "REST Web Service API Role."
If you wish to track licence usage, then use this Dashboard, but note that you have to have the KPI running in order for it to tally up the counts over time:
License Usage - CA Service Management - 17.1 - CA Technologies Documentation