The Notice to Airmen (NOTAM) has been around for a long time and is commonly used to distribute information about an airport or airway facility to the general pilot population.
There arecurrently three main types of NOTAMs. Notam-L, Notam-D, and Notam-FSD. Notam-L is used to inform pilots about events on an airport that do not affected the pilots ability to land at the airport. For example, if a taxiway is closed it would be listed as a NOTAM-L. Notam-D's are notams that do affect a pilots ability to land at the airport, for example if a runway is closed. Notam-FSD's are notams entered into the notam system by the flight service station and include items like the ILS out of service, a tower not lighted, etc.
The entire Flight Service System is undergoing a complete overhaul currently by the Lockheed Corporation and some of the service you have grown to know and love will may longer exist, but first how did a private corporation gain control over a government service.
a few years ago the FAA wanted to limit the cost incured by the Flight Service System and started consolidating many of the flight service stations. This worked in saving some costs but there was still many costs that the FAA felt where unnessary. Then not too long ago the FAA asked some business directly invovled in aviation or aviation weather to submit to them proposals on how the FSS could be privatized.
Without going into if this was a wise move, Lockheed won the contract over compaies that have done flight planning in the past or do it now. some of the compeditors where Jepasen and Duat to name a few. Lockheeds proposal was to keep only 16 (i think) FSS closing the rest. In their initial proposal Lockheed only accounted for NOTAMS which would close down ILS or airway equipment.
The big problem is they would not do NOTAM-D or NOTAM-Ls anymore. As time past they received pressure to change their ways, but we still need to know from Lockheed if they plan to report any notam other than Airway Notams.