With teams of readers scattered across many geographical markets, they would monitor print media for specific keywords and then snip out the articles, mark the keywords in the margin, and mail the client binders with all the relevant clippings.
Clipping services also advertised in art magazines for illustrators who wanted to collect tearsheets of other artists or photos of certain cities or subjects.
Is it a case of Death by Google? Some of these companies have shifted to monitor digital media, or they've merged or gone the way of the dodo.
But there are still players in the print-clipping game because a lot of print media is hidden behind paywalls.