It is also an industry standard by the name IEEE 1295. It was and still is used as the basic building blocks for the Common Desktop Environment. As of version 2.1 Motif supports Unicode which has made it widely used in several multilingual environments.
Motif is distinguished by its use of square, chiseled, three dimensional effects for the various user interface elements -- menus, buttons, sliders, text boxes, and the like. This was in vogue, however, as Microsoft Windows 3.x had added a 3D effect and Motif on UNIX was increasingly seen as a competitor to Microsoft on Intel personal computers.
Many argue that it is practically obsolete when compared to GTK or Qt (a key indicator is that the major Motif user Sun Microsystems have declared that they will switch over to GTK and GNOME), but it is still used in many legacy systems.