I saw one for the first time while walking past a poster of the Jennifer Aniston pic, Rumor Has It, yesterday: a big empty white word balloon coming right out of the Friend’s mouth. I thought it was part of the poster, its blank space some sort of Kaufman-esque pitch having to do with the vapidity of celebrity culture. But at the 14th St. station tonight, I saw a few more, on different posters, and I realized that these professionally printed stick-ons are some artist/prankster’s works of media detournement. Amplifying the intention of the movie poster — to “draw you in” — to a personal degree, they prompt the passerby to approach the poster to sample his fellow citizens’ scrawled-on wit or, perhaps, to whip out a marker himself and add a comment.

There’s something implicitly challenging about these word balloons. Interrupting the one-sheet’s message, they change a movie poster from iconic urban wallpaper, just one of the many advertising hits you’ll see before you “decide” to see a film, to communal signs that cry out for evaluation and critique. So, for me, I was a little bummed when I walked across the long corridor leading from the “A” train to the “L” to see what someone had filled into the cartoon balloon afixed next to the pondering man on the Munich poster. “Another Hollywood blockbuster,” the graffitist had him saying.

If I don’t start reading better material as I walk around the city the next few days, I’m going to have to start carrying a black marker.