The organization behind ".um", the University of Southern California's Information Sciences Institute, decided the domain wasn't worth the effort. Since it wasn't being used anyway, the Internet Corporation for Assigned Names and Numbers unanimously decided last week to eliminate it entirely, bringing the list of domains to 264. The public's opinion on how to revoke outdated suffixes is being taken into consideration in order to trim the domain list down. Domains tied to countries that no longer exist are the prime target. Soviet Union's ".su" is the leading candidate for deletion but a Google search still displays more than 3 million ".su" sites. Recent new domain names include ".eu" and ".travel" while ".xxx" is still under ICANN review.
News source: Physorg