The DUAT (Direct User Access Terminal) system is an online weather briefing and flight planning service created in 1989 when the FAA awarded contracts to two companies, Computer Sciences Corp. (CSC) and Data Transformation Corp. (DTC), after an open bidding process. The two companies process millions of transactions a year, with a transaction defined by the FAA as a 15-minute chunk of time. In that time frame, pilots can check weather, check NOTAMs, and file several flight plans. According to FAA data, the number of DUAT weather briefings outnumbers those provided by Flight Service Stations by a margin of five to one.
For more information: DUAT.com (for DTC DUAT services) or DUATS.com (for CSC).