Morgan Spurlock, the thinner, gentler variant of Michael Moore, continues his string of first-person documentaries with this humorous screed against product-placement in movies and television. As usual with such one-joke projects, “POM Wonderful Presents The Greatest Movie Ever Sold” seems a bit overlong even at under ninety minutes, but it offers enough smiles and insights to earn a low passing grade.

The premise is pretty straightforward: Spurlock aims to make the picture by securing sponsors to cover the $1.5 million cost, and the footage follows him from firm to firm as he gets advice from advertising men about how to proceed and then does presentations before the boards of prospective sponsors whom he promises positive coverage in the picture in return for their funding. He adds to this his own wry commentary on the process, interviews with cultural observers like Ralph Nader and Noam Chomsky, and his efforts to fulfill his contractual obligations about getting word out about the film through advertising gimmicks and TV appearances.

Spurlock is an ingratiating presence here, less smugly silly than in some of his previous movies (like his “search” for Osama bin Laden); and he’s humanized by references to his young son, whom we actually meet toward the close. He and editors Thomas M. Vogt and Marian Cho get laughs through their rat-a-tat montages of clips from movies and TV shows in which advertising is none too surreptitiously inserted into the narrative, and even louder ones by pointing out instances in their own footage involving the “sponsors” Spurlock’s convinced to invest in his project. Observations by established directors like Brett Ratner and Peter Berg reinforce the point, as do visits with pros who arrange for product placement and go to great lengths to prevent misuse of their clients’ stuff. The thirty-second spots for the film’s main sponsors are amusing as well, though to be honest the pitches that Spurlock makes at one point to the POM board are a lot funnier than the ideas they push on him.

There are also some detours from the levity. An episode about advertising in schools doesn’t get overly didactic, but makes a point, as does a visit to Sao Paolo, where a government ban on outdoor advertising has radically altered the look—and ambiance—of the city.

Spurlock isn’t saying anything here that hasn’t been said before. The tendency of advertising to creep in everywhere, and the insidious effort to camouflage it by inserting it into “entertainment” (just a step above the old bugaboo of subliminal messages) are hardly unexplored topics. But they’re treated here in an amusing fashion that makes them easy to take, and to agree with.