"Now, NCTC can copy entire government databases—flight records, casino-employee lists, the names of Americans hosting foreign-exchange students and many others. The agency has new authority to keep data about innocent U.S. citizens for up to five years, and to analyze it for suspicious patterns of behavior. Previously, both were prohibited. Data about Americans "reasonably believed to constitute terrorism information" may be permanently retained."
Go RTWT, you really need to know this.