Very well explained--as far as it goes. But you must add the difference between ADS-B/IN and /OUT. Not only will this tell the reader that in the context in which you are writing--the missing 777--what data ADS-B makes available is very different in its usefullness. Also, there is no "business case" for /OUT for any airline such as Malaysian but there is a powerful one for /IN. However, the FAA is only funding the ground stations for /OUT which is one of worst public (FAA) decisions ever (for which no FAA executive has ever paid any price).