Family Tree Maker was first a DOS program. The abbreviation used was FTM. Then a Windows version came out, and we began using FTW to differentiate between the two. Some people who have been using Family Tree Maker since the time when both DOS and Windows versions were being used still use that nomenclature. Nowadays, FTM and FTW can both be used (as the DOS version was last updated about 5 years ago), and we assume you are talking about the Windows version.