Excerpt from the FBI report:

> Pen Register: Sent every 15 minutes, provides source and destination of every message. [without a warrant of any kind]

(And who knows what other three letter agencies can get.)

BuT ThAt'S jUsT mEtAdAta, wE hAvE nOtHinG tO hIdE. Then keep using it, but don't spread your bullshit to others.