According to documents leaked by Edward Snowden: "The MARINA metadata application tracks a user's browser experience, gathers contact information/content and develops summaries of target" and "of the more distinguishing features, MARINA has the ability to look back on the last 365 days' worth of DNI metadata seen by the SIGINT collection system, regardless whether or not it was tasked for collection." [Emphasis in original NSA document.]
MARINA stored metadata is mainly used for pattern-of-life analysis. United States Citizens are not exempt because metadata is not considered data by United States law (section 702 of the Foreign Intelligence Surveillance Act (FISA)
MARINA's phone counterpart is MAINWAY
MARINA is fed from FALLOUT