At my University there is a course called “Programming with Motif”
It being quite an old framework, I am wondering where motif / programs made with motif are used today.
It tends to be used in old software (i.e. software which has been around for a long time, not necessarily obsolete software); for example:
For some reason lots of "scientific" software still uses Motif: ARB, ESO-MIDAS... And some software still supports Motif, although by default it doesn't use it any more; as schaiba mentioned, Emacs can be built to use Motif.