Are you not aware of the little thing called the patriot act? There's no need for a subpoena anymore, even when one was required it could be gotten in less than a day with probable cause as justification just like most search warrants. Cops were busting people as far back as the 90's, not even getting into what the feds were doing on their own. MANY communication companies will freely give out some information with a simple call from a detective, private detectives use this tactic all the time posing as police officers without any paperwork or court orders, there's also the added justification that most states have laws(felony offenses) for using communication devices of any kind in the commission of various crimes.