public service anouncement

Public service announcements are when people inform you about important things about what is going on in the world. This is the top ten public service announcements.

http://content.time.com/time/specials/packages/article/0,28804,1920454_1920455_1920431,00.html

This is all about public service announcements so you can find out about what they are. 

http://www.acep.org/ACEP-Taxonomy-of-Subject-Matterews-/All-About-Public-Service-Announcements/