I think it is called Global Entry. I still need to apply for it but in the meantime I have TSA Precheck and Clear. That makes the line much shorter.I applied for the more expensive option (Global something?) and then the ********* screwed me. My husband has TSA Precheck and he never remembers to use it.
All you have to do is add the KTN for Precheck to your account on that airline. Since I fly Southwest airline most of the time, it is easy. My KTN is on it. For American airline I had to add it while booking my ticket on line.
In the Clear line I am often the only one. However recently at Denver airport there were 4-5 people ahead of me.