THE hit podcast Serial was the audio investigation that launched a thousand true crime dramas, inspiring podcasters across the country to attempt ambitious reporting projects with gritty subject matter. There were Dirty John and Hollywood & Crime,Death in Ice Valley and Atlanta Monster.

And then there was The Sauce. That three- episode "investigative podcast" was released last year by the media company Gizmodo and had somewhat lower stakes than the exoneration of a convicted murderer. With an eerie soundtrack meant to recall Serial, the show examined the "mystery" of how McDonald's underestimated demand for a popular dipping sauce, enraging thousands of its customers. The twist? The hard-boiled investigator scrutinising that sauce shortage was McDonald's itself.

The Sauce was a branded podcast that McDonald's paid Gizmodo to produce as a tongue-in-cheek apology to disappointed customers. While it was no exposé, the show offers a vivid illustration of how companies are increasingly using the tropes of popular podcasts in their own audio projects. These are not advertisements, exactly, but subtle brand-building efforts intended to entertain as well as persuade.