Eventually, this app will be a one stop place to access other current CPB appls like Mobile Passport. If you are part of a Trusted Traveler program you will be able to manage it through this app--including those applying.
Nigel, CPB already tracks people. No need for an app. Anytime you board an airplane bound for the U.S., leaving the U.S., or the plane even flies over the U.S., your information is sent to Homeland Security. Everyone's. A computer then scans that information to make sure you aren't on the no fly list. This is also done for domestic flights.
Whether or not we're being tracked, I don't know. But a couple of years ago when I went for my Global Entry renewal interview, the agent asked me about my visit to the Channel Islands. He wasn't sure where that was. How he knew I went there is beyond me as I arrived from London so no border crossing.
For those who don't trust our government, get real, they know more about you than you think.