Consumers can look up any ISSN at WorldCat.org, according to the U.S. ISSN Center. The center assigns International Standard Serial Numbers to every serial printed in the United States.
The U.S. ISSN Center states that an ISSN can be considered the "Social Security number for the serials world." As a Social Security number distinguishes a person from everyone else, an ISSN distinguishes one serial from all others. This is particularly helpful when a serial has the same name as another. WorldCat.org connects to more than two billion serials, so a person can find any existing ISSN by searching through this website.