The list of top level domains just got shorter. ICANN, the organization which administers all top level domains recently decided to erase the .UM domain (US Minor outlying islands) because University of Southern California's Information Sciences Institute no longer wanted to operate the TLD.
There are other top level domains which probably will be deleted soon. The top level domain for the Soviet Union .US is a candidate for deletion. Another tld to be deleted is .TP (East Timor) which has been replaced by .TL (Timor Leste).