What Makes Up the Name: advertising + editorial
You know those special sections in magazines that look kind of like the editorial content but are about how great this Ford Focus' stereo is and it seems weird that they're talking about it for two pages? Well, that's not content, that's an ad. Or more accurately, it is ad sales' bevloed, advertorial.
Origin: The NYT mentions the term in a 1979 piece noting US News and World Report's upcoming Nov. 19 issue.