In the creative brief, right under the media plan summary, there should be a description of each media property and the particularities of its audience. Which means there's a job for someone to do nothing but watch TV, read magazines, browse the web, and take lots of notes, sort of a mix between an account and media planners. After all, we have well-paid professionals hunting down and explaining obscure cultural phenomena - why not somebody who keeps track of the stuff that's popular today. Somebody who'd work in the Chief Culture Officer's department.
Or maybe it could be an industry publication, CliffsNotes for popular media culture. Wonder if there isn't one already.
Then we'd have more ads that enhance the primary media experience instead of interrupting it, like these Target's 15" spots that ran during Lost finale.